Modified Polyethylene Compositions with Enhanced Melt Strength

ABSTRACT

The present invention relates to a branched modifier and a composition comprising more than 25 wt % (based on the weight of the composition) of one or more linear ethylene polymers having a g′ vis  of 0.97 or more and an Mw of 20,000 g/mol or more and at least 0.1 wt % of a branched modifier where the modifier has a) a g′ vis  of 0.70 or less; b) an Mw of 100,000 g/mol or more; c) an Mw/Mn of 4.0 or more; d) a shear thinning ratio of 110 or more, e) a melt strength of 10 cN or more; f) a complex viscosity at 0.1 rad/sec at 190° C. of at least 130,000 Pa·s; and g) a phase angle of Z° or less where Z=138.3 G* (−0.142) , where G* is the complex modulus reported in Pascals measured at 190° C. and the phase angle units are reported in degrees, wherein the G* is from 1,000 to 1,000,000 Pa.

US PRIORITY CLAIM

This application is a continuation-in-part of U.S. application Ser. No.13/623,242, filed Sep. 20, 2012, which claims the benefit of andpriority to U.S. Application No. 61/538,703, filed Sep. 23, 2011 andEuropean Application No. 11188165.2, filed Nov. 8, 2011.

FIELD OF THE INVENTION

The present invention relates to branched modifiers, and polyethylenecompositions comprising an ethylene based polymer and a branchedmodifier. More particularly, the present invention relates topolyethylene compositions having significantly improved properties suchas melt strength or extensional strain hardening, without substantialloss in mechanical properties.

BACKGROUND OF THE INVENTION

For many polyolefin applications, including films and fibers, increasedmelt strength and good optical properties are desirable attributes.Higher melt strength allows fabricators to run their blown film lines ata faster rate. It also allows them to handle thicker films inapplications such as geomembranes.

Typical metallocene catalyzed polyethylenes (mPE) are somewhat moredifficult to process than low-density polyethylenes (LDPE) made in ahigh-pressure polymerization process. Generally, mPEs (which tend tohave narrow molecular weight distributions and low levels of branching)require more motor power and produce higher extruder pressures to matchthe extrusion rate of LDPEs. Typical mPEs also have lower melt strengthwhich, for example, adversely affects bubble stability during blown filmextrusion, and are prone to melt fracture at commercial shear rates. Onthe other hand, mPEs exhibit superior physical properties as compared toLDPEs. In the past, various levels of LDPE have been blended with themPE to increase melt strength, to increase shear sensitivity, i.e. toincrease flow at commercial shear rates in extruders; and to reduce thetendency to melt fracture. However, these blends generally have poormechanical properties as compared with neat mPE. It has been a challengeto improve mPEs processability without sacrificing physical properties.

U.S. Publication No. 2007/0260016 discloses blends of linear low densitypolyethylene copolymers with other linear low density polyethylenes orvery low density, low density, medium density, high density, anddifferentiated polyethylenes, as well as articles produced therefrom.U.S. Publication No. 2007/0260016 does not appear to disclose means toobtain a balance of improved processability and physical properties.

Guzman, et al., AIChE Journal, May 2010, Vol. 56, No. 5, p. 1325-1333discloses ethylene/octene/1,9-decadiene copolymers and a method topredict gel formation in the production thereof. The publication issilent on the technical features that would be needed to make thedecadiene terpolymer suitable for providing the optimum balance ofprocessability and physical properties.

U.S. Pat. No. 6,300,451 discloses ethylene/butene/1,9-decadienecopolymers, and ethylene hexene vinyl norbornene copolymers (see TablesI and II). The decadiene terpolymers disclosed are designed to be usedalone and not in blends for improved processability/property balance.The relatively high MI of the resins suggests that they would not besuitable in blends which exhibit improved extensional strain hardening.

U.S. Pat. No. 5,670,595 discloses diene modified polymers, particularlydiene modified propylene polymers that would not be suitable formodification of polyethylene based polymers due to theirincompatibility.

U.S. Pat. No. 6,509,431 discloses ethylene/hexene/1,9 decadienecopolymers. The low melt index ratio of the disclosed polymers suggeststhat they would not be suitable for rheology modification (increasedstrain hardening) of the base linear polyethylene.

Other references of interest include: U.S. Pat. Nos. 7,687,580;6,355,757; 6,391,998; 6,417,281; 6,114,457; 6,734,265; 6,147,180; andPCT Publication Nos. WO 2007/067307; WO 2002/085954.

We have discovered that certain branched hydrocarbon modifiers,preferably comprising dienes, will advantageously improve processabilityof polyethylene without significantly impacting its mechanicalproperties. Moreover, addition of these branched hydrocarbon modifiersprovides a means to change such properties on a continuous scale, basedon real-time needs, which is typically not possible due to theavailability of only discrete polyethylene grades. Furthermore, adifferent set of relationships between processability and properties isobtained, compared to those available from traditional polyethylenes andtheir blends with conventional LDPE, which allows for new andadvantageous properties of the fabricated articles.

SUMMARY OF THE INVENTION

This invention relates to branched polyethylene modifiers comprising atleast 50 mol % ethylene, one or more C₄ (preferably C₆) to C₄₀comonomers, and a polyene having at least two polymerizable bonds,wherein said branched polyethylene modifier: a) has a g′_(vis) of 0.70or less; b) has an Mw of 100,000 g/mol or more; c) has an Mw/Mn of 4.0or more; d) a shear thinning ratio of 110 or more; e) melt strength of10 cN or more, f) a complex viscosity at 0.1 rad/sec at 190° C. of atleast 130,000 Pa·s; and g) has a phase angle of Z° or less where Z=138.3G*⁽⁻⁰¹⁴²⁾, where G* is the complex modulus reported in Pascals measuredat 190° C. and the phase angle units are reported in degrees, whereinthe G* is from 1,000 to 1,000,000 Pa.

This invention further relates to polyethylene compositions comprisingone or more ethylene polymers and one or more branched polyethylenemodifiers where the modifier has a complex viscosity ratio of Y or more,where Y−0.27*Log η*_(matrix)+1.4, the complex viscosity ratio is definedto be, (Log η*_(modifier)−Log η*_(matrix))/Log η*_(matrix), andη*_(modifier) is the complex viscosity of the modifier measured at 0.1rad/sec and 190° C., η*_(matrix) is the complex viscosity of theethylene polymer measured at 0.1 rad/sec and 190° C.

This invention also relates to a blend comprising:

1) branched polyethylene modifier comprising at least 50 mol % ethylene,one or more C₄ (preferably C₆) to C₄₀ comonomers, and a polyene havingat least two polymerizable bonds, wherein said branched polyethylenemodifier has: a) a g′_(vis) of 0.70 or less; b) an Mw of 100,000 g/molor more; c) an Mw/Mn of 4.0 or more; d) a shear thinning ratio of 110 ormore, e) a melt strength of 10 cN or more; f) a complex viscosity at 0.1rad/sec at 190° C. of at least 130,000 Pa·s; g) a phase angle of Z° orless where Z=138.3 G*^((−00.142)), where G* is the complex modulusreported in Pascals measured at 190° C. and the phase angle units arereported in degrees, wherein the G* is from 1,000 to 1,000,000 Pa,wherein the G* is from 1,000 to 1,000,000 Pa; and h) a complex viscosityratio of Y or more, where Y=−0.27*(Log η*_(matrix))+1.4, and the complexviscosity ratio is defined to be (Log η*_(modifier) minus Logη*_(matrix)) divided by (Log η*_(matrix)), wherein η*_(modifier) is thecomplex viscosity of the modifier measured at 0.1 rad/sec and 190° C.,and η*_(matrix) is the complex viscosity of the polyethylene of step 2)below measured at 0.1 rad/sec and 190° C., complex viscosity is measuredas described below and is reported in units of Pa·s;2) polyethylene having a density of 0.88 g/cm³ or more and an Mw of20,000 g/mol or more; wherein the melt strength ratio is Q or more,where Q=0.0805[(η*modifier−η*_(matrix))/(η*_(matrix))]+0.5, whereinη*_(modifier) is the complex viscosity of the modifier measured at 0.158rad/sec and 190° C., and η*_(matrix) is the complex viscosity of thepolyethylene measured at 0.158 rad/sec and 190° C.; and the meltstrength ratio is defined to be[(MS_(blend)−MS_(matrix))/(MS_(matrix))], where MS_(blend) is the meltstrength of the blend, MS_(matrix) is the melt strength of thepolyethylene, melt strength is reported in cN and measured according tothe procedure in the Test Methods section below.

This invention also relates to a polyethylene composition comprising oneor more ethylene polymers having a density of 0.88 g/cc or more, ag′_(vis) of 0.97 or more, and an Mw of 20,000 g/mol or more, and one ormore branched polyethylene modifiers where the modifier has a complexviscosity ratio of Y or more, where Y−0.27*Log η*_(matrix)+1.4, thecomplex viscosity ratio is defined to be (Log η*_(modifier)−Logη*_(matrix))/Log η*_(matrix), and η*_(modifier) is the complex viscosityof the modifier measured at 0.1 rad/sec and 190° C., η*_(matrix) is thecomplex viscosity of the ethylene polymer measured at 0.1 rad/sec and190° C.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a Van Gurp-Palmen plot (phase angle vs. complex shear modulus)of the branched polyethylene modifiers produced in Examples 1 to 4 andExceed™ 2018 polyethylene.

FIG. 2 provides a comparison of the shear thinning characteristics ofthe branched polyethylene modifiers produced in Examples 1 to 4 andExceed™ 2018 polyethylene.

FIG. 3 provides a comparison of the shear thinning characteristics ofthe branched polyethylene modifiers produced in Examples 5 to 10 andExceed™ 2018 polyethylene.

FIG. 4 is a Van Gurp-Palmen plot (phase angle vs. complex shear modulus)of branched polyethylene modifiers in Examples 5 to 10 and Exceed™ 2018polyethylene.

FIG. 5 depicts the transient uniaxial extensional viscosity of thebranched polyethylene modifiers in Examples 1 and 5 as a function oftime, showing strain hardening.

FIG. 6 depicts the transient uniaxial extensional viscosity of theinventive polymer composition in Examples 12 to 15 as a function oftime.

DEFINITIONS

An “olefin,” alternatively referred to as “alkene,” is a linear,branched, or cyclic compound of carbon and hydrogen having at least onedouble bond. For purposes of this specification and the claims appendedthereto, when a polymer or copolymer is referred to as comprising anolefin, including, but not limited to ethylene, hexene, and diene, theolefin present in such polymer or copolymer is the polymerized form ofthe olefin. For example, when a copolymer is said to have an “ethylene”content of 35 wt % to 55 wt %, it is understood that the mer unit in thecopolymer is derived from ethylene in the polymerization reaction andsaid derived units are present at 35 wt % to 55 wt %, based upon theweight of the copolymer. A “polymer” has two or more of the same ordifferent mer units. A “homopolymer” is a polymer having mer units thatare the same. A “copolymer” is a polymer having two or more mer unitsthat are different from each other. A “terpolymer” is a polymer havingthree mer units that are different from each other. The term “different”as used to refer to mer units indicates that the mer units differ fromeach other by at least one atom or are different isomerically.Accordingly, the definition of copolymer, as used herein, includesterpolymers and the like. Likewise, the definition of polymer, as usedherein, includes copolymers and the like. Thus, as used herein, theterms “polyethylene,” “ethylene polymer,” “ethylene copolymer,” and“ethylene based polymer” mean a polymer or copolymer comprising at least50 mol % ethylene units (preferably at least 70 mol % ethylene units,more preferably at least 80 mol % ethylene units, even more preferablyat least 90 mol % ethylene units, even more preferably at least 95 mol %ethylene units or 100 mol % ethylene units (in the case of ahomopolymer)). Furthermore, the term “polyethylene composition” means ablend containing one or more polyethylene components.

For purposes of this invention and the claims thereto, an ethylenepolymer having a density of 0.86 g/cm³ or less is referred to as anethylene elastomer or elastomer; an ethylene polymer having a density ofmore than 0.86 to less than 0.910 g/cm³ is referred to as an ethyleneplastomer or plastomer; an ethylene polymer having a density of 0.910 to0.940 g/cm³ is referred to as a low density polyethylene; and anethylene polymer having a density of more than 0.940 g/cm³ is referredto as a high density polyethylene (HDPE). For these definitions, densityis determined using the method described under Test Methods below.

Polyethylene in an overlapping density range, i.e. 0.890 to 0.930 g/cm³,typically from 0.915 to 0.930 g/cm³, which is linear and does notcontain long chain branching is referred to as “linear low densitypolyethylene” (LLDPE) and can be produced with conventionalZiegler-Natta catalysts, vanadium catalysts, or with metallocenecatalysts in gas phase reactors and/or in slurry reactors and/or withany of the disclosed catalysts in solution reactors. “Linear” means thatthe polyethylene has no long chain branches, typically referred to as ag′_(vis) of 0.97 or above, preferably 0.98 or above.

Composition Distribution Breadth Index (CDBI) is a measure of thecomposition distribution of monomer within the polymer chains and ismeasured by the procedure described in PCT Publication No. WO 93/03093,published Feb. 18, 1993, specifically columns 7 and 8 as well as in Wildet al, J. Poly. Sci., Poly. Phys. Ed., Vol. 20, p. 441 (1982) and U.S.Pat. No. 5,008,204, including that fractions having a weight averagemolecular weight (Mw) below 15,000 are ignored when determining CDBI.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a branched polyethylene modifier comprising atleast 50 mol % ethylene (preferably at least 70 mol % or more,preferably at least 90 mol % or more), one or more C₄ (preferably C₆) toC₄₀ comonomers (preferably 50 mol % or less, preferably 30 mol % orless, preferably from 0.5 to 30 mol %, preferably 1 to 25 mol %), and apolyene having at least two polymerizable bonds (preferably from 0.001to 10 mol %, preferably from 0.01 to 5 mol %), wherein said branchedpolyethylene modifier has: a) a g′_(vis) of 0.70 or less (preferably0.65 or less, preferably 0.60 or less, preferably 0.55 or less,preferably 0.50 or less); b) an Mw of 100,000 g/mol or more, (preferably120,000 or more, preferably 150,000 or more, preferably 200,000 ormore); c) an Mw/Mn of 4.0 or more (preferably 4.5 or more, preferably5.0 or more, preferably 6.0 or more, preferably 7.0 or more, preferably8.0 or more, preferably 9.0 or more, preferably from 4.0 to 40); d) ashear thinning ratio of 110 or more (preferably 120 or more, preferably130 or more, preferably 140 or more, preferably 150 or more, preferablyfrom 110 to 300), e) a melt strength of 10 cN or more (preferably 15 ormore, preferably 20 or more, preferably 25 or more, preferably 30 ormore); f) a complex viscosity at 0.1 rad/sec at 190° C. of at least130,000 Pa·s (preferably 150,000 or more, preferably 200,000 or more,preferably 250,000 or more, preferably 300,000 or more, preferably400,000 or more, preferably 500,000 or more); and g) a phase angle of Z°or less where Z=138.3 G*^((−00.142)), where G* is the complex modulusreported in Pascals measured at 190° C. and the phase angle units arereported in degrees, wherein the G* is from 1,000 to 1,000,000 Pa(preferably Z=138.3 G*^((−0.142))−2, preferably Z=138.3G*^((−0.142))−5).

This invention relates to polyethylene compositions, preferablypolyethylene blends, comprising one or more ethylene polymers and one ormore branched modifiers (also referred to as a branched modifier polymeror branched polyethylene modifier), preferably comprising long chainbranched polyethylene polymers.

This invention further relates to a composition comprising more than 25wt % (based on the weight of the composition) of one or more ethylenepolymers having a g′_(vis) of 0.97 or more and an Mw of 20,000 g/mole ormore, and at least 0.1 wt % (based on the weight of the composition) ofa branched polyethylene modifier where the modifier has a) a g′_(vis) of0.70 or less; b) an Mw of 100,000 g/mol or more; c) an Mw/Mn of 4.0 ormore; d) a shear thinning ratio of 110 or more, e) melt strength of 10cN or more; f) a complex viscosity at 0.1 rad/sec at 190° C. of at least130,000 Pa·s; g) a phase angle of Z° or less where Z=138.3 G*^((−0.142))where G* is the complex modulus reported in Pascals measured at 190° C.and the phase angle units are reported in degrees, wherein the G* isfrom 1,000 to 1,000,000 Pa, and h) a complex viscosity ratio of Y ormore, where Y=−0.27*Log η*_(matrix)+1.4, and the complex viscosity ratiois defined to be

,(Log η*_(modifier)−Log η*_(matrix))/Log η*_(matrix),

wherein η*^(modifier) is the complex viscosity of the modifier measuredat 0.1 rad/sec and 190° C., and η*_(matrix) is the complex viscosity ofthe polyethylene measured at 0.1 rad/sec and 190° C.; wherein the meltstrength ratio is Q or more, whereQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+0.5, whereinη*_(modifier) is the complex viscosity of the modifier measured at 0.158rad/sec and 190° C., and η*_(matrix) is the complex viscosity of thepolyethylene measured at 0.158 rad/sec and 190° C.; and the meltstrength ratio is defined to be[(MS_(blend)−MS_(matrix))/(MS_(matrix))], where MS_(blend) is the meltstrength of the composition, MS_(matrix) is the melt strength of thepolyethylene, melt strength is reported in cN and measured according tothe procedure in the Test Methods section below.

In another embodiment, the ratio of the complex viscosity of thebranched modifier to the complex viscosity of the ethylene polymercomponent in the blend composition (i.e. η*modifier/(η*matrix) isgreater than 3 (preferably greater than 3.5, preferably greater than 5,preferably greater than 10, preferably greater than 15, preferablygreater than 20, preferably greater than 25, preferably greater than 30)when the complex viscosity is measured at a frequency of 100 rad/sec anda temperature of 190° C. according to the procedure described in theTest Methods section below.

In another embodiment, this invention further relates to a compositioncomprising: 1) from 99.99 wt % to 50 wt % (preferably from 75 wt % to99.9 wt %, preferably from 90 wt % to 99.9 wt %, preferably from 95 wt %to 99.5 wt %, preferably from 96 wt % to 99.5 wt %, preferably from 97wt % to 99.5 wt %, preferably from 98 wt % to 99 wt %), based upon theweight of the blend, of a linear ethylene polymer having:

a) a branching index, g′_(vis), (determined according the proceduredescribed in the Test Methods section below) of 0.97 or more, preferably0.98 or more, preferably 0.99 or more; and

b) a density of 0.860 to 0.980 g/cm³ (preferably from 0.880 to 0.940g/cc, preferably from 0.900 to 0.935 g/cc, preferably from 0.910 to0.930 g/cc);

c) an Mw of 20,000 g/mol or more (preferably 20,000 to 2,000,000 g/mol,preferably 30,000 to 1,000,000, more preferably 40,000 to 200,000,preferably 50,000 to 750,000); and 2) from 0.01 wt % to 50 wt %(preferably from 0.1 wt % to 25 wt %, preferably from 0.1 wt % to 10 wt%, preferably from 0.5 wt % to 5 wt %, preferably from 0.5 wt % to 4 wt%, preferably from 0.5 wt % to 3 wt %, preferably from 1 wt % to 2 wt%), based upon the weight of the blend, of a branched modifier,preferably comprising a terpolymer of ethylene, a C₄ to C₂₀alpha-olefin, and a diene, said modifier having:

i) a g′_(vis) of less than 0.70 (preferably 0.65 or less, preferably0.60 or less, preferably 0.55 or less, preferably 0.50 or less);

ii) a density of from about 0.850 to about 0.980 g/cm³ (preferably from0.890 to about 0.980, preferably from 0.880 to 0.940 g/cc, preferablyfrom 0.900 to 0.935 g/cc, preferably from 0.910 to 0.930 g/cc);

iii) a molecular weight distribution (Mw/Mn) of from about 2.5 to about40 (alternately 4.0 to 40, alternately 5.0 to 40, alternately 6.0 to 30,alternately 7.0 to 20); iv) an Mw of 100,000 g/mol or more, (preferably120,000 or more, preferably 150,000 or more, preferably 200,000 ormore);

v) a shear thinning ratio of 110 or more (preferably 120 or more,preferably 130 or more, preferably 140 or more, preferably 150 or more,preferably from 110 to 300),

vi) a melt strength of 10 cN or more (preferably 15 or more, preferably20 or more, preferably 25 or more, preferably 30 or more);

vii) a complex viscosity at 0.1 rad/sec at 190° C. of at least 130,000Pa·s (preferably 150,000 or more, preferably 200,000 or more, preferably250,000 or more, preferably 300,000 or more, preferably 400,000 or more,preferably 500,000 or more);

viii) a phase angle of Z° or less where Z=138.3 G*^((−00.142)), where G*is the complex modulus reported in Pascals measured at 190° C. and thephase angle units are reported in degrees, wherein the G* is from 1,000to 1,000,000 Pa (preferably Z=138.3 G*^((−0.142))-2, preferably Z=138.3G*^((−0.142))−5); and

ix) a complex viscosity ratio of Y or more, where Y=−0.27*(Logη*_(matrix))+1.4, and the complex viscosity ratio is defined to be [(Logη*_(modifier)) minus (Log η*_(matrix))] divided by (Log η*_(matrix)),wherein η*_(modifier) is the complex viscosity of the modifier measuredat 0.1 rad/sec and 190° C., and η*_(matrix) is the complex viscosity ofthe linear polyethylene measured at 0.1 rad/sec and 190° C., preferablyY=−0.28*(Log η*_(matrix))+1.5, preferably Y=−0.2954*(Logη*_(matrix))+1.6065;

where the melt strength ratio is Q or more, where

Q=0.0805[(η*_(modifier) minus η*_(matrix)) divided by(η*_(matrix))]+0.5, where η*_(modifier) is the complex viscosity of themodifier measured at 0.158 rad/sec and 190° C., and η*_(matrix) is thecomplex viscosity of the linear polyethylene measured at 0.158 rad/secand 190° C.; and the melt strength ratio is defined to be [(MS_(blend)minus MS_(matrix)) divided by (MS_(matrix))], where MS_(blend) is themelt strength of the composition, MS_(matrix) is the melt strength ofthe linear polyethylene, melt strength is reported in cN and measuredaccording to the procedure in the Test Methods section below, preferablyQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+0.75, preferablyQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+1.0, preferablyQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+1.4, preferablyQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+1.4988.

In any embodiment described herein the composition of linear PE andbranched modifier has an elasticity ratio of Z* or more, whereZ*=0.009*(δ_(matrix))+0.05, where the elasticity ratio is defined to be[(δ_(matrix)−δ_(modifier))/(δ_(matrix))], where δ_(matrix) is the phaseangle of the linear polyethylene measured at a complex modulus of100,000 Pa, δ_(modifier) is the phase angle of the branched modifier ata complex modulus of 100,000 Pa, where phase angle is determined asdescribed below, preferably Z*=0.008*(δ_(matrix))+0.14, preferablyZ*=0.0079*(δ_(matrix))+0.1318.

In any embodiment described herein the composition of linear PE andbranched modifier blend has a melt strength ratio of T or more, whereT=0.1.6762[(η*_(blend) minus η*matrix) divided by (η*matrix)]−5, whereη*_(blend) is the complex viscosity of the blend measured at 0.158rad/sec and 190° C., and η*_(matrix) is the complex viscosity of thelinear polyethylene measured at 0.158 rad/sec and 190° C.; and the ratioof melt strength to viscosity is defined to be melt strength ratio isdefined to be [(MS_(blend) minus MS_(matrix)) divided by (MS_(matrix))],where MS_(blend) is the melt strength of the composition, MS_(matrix) isthe melt strength of the linear polyethylene, melt strength is reportedin cN and measured according to the procedure in the Test Methodssection below, preferably T=0.1.6762[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+0, preferably T=0.1.6762[(η*_(blend) minusη*_(matrix)) divided by (η*_(matrix))]+5, preferablyT=0.1.6762[(η*_(blend) minus η*_(matrix)) divided by (η*_(matrix))]+10,preferably T=0.1.6762[(η*_(blend) minus η*_(matrix)) divided by(η*_(matrix))]+15, preferably T=0.1.6762[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+16.153. Alternately T is equal to2.1957[(η*_(blend) minus η*_(matrix)) divided by (η*_(matrix))]+30,preferably T=2.1957[(η*_(blend) minus η_(matrix)) divided by(η*_(matrix))]+40, preferably T=2.1957[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+50, preferably T=2.1957[(η*_(blend) minusη*_(matrix)) divided by (η*_(matrix))]+60.

In another embodiment, the branched modifier has a compositiondistribution breadth index of at least 60% and/or a melt index (ASTM1238, 190° C., 2.16 kg) of 15 dg/min or less.

In some embodiments, compositions include a polymer blend composed of anethylene polymer and any of the branched modifier polymers describedherein, preferably a metallocene-catalyzed branched modifier polymer.The ethylene polymer of the blend includes any of the ethylene polymersdescribed herein, preferably, a metallocene-catalyzed ethylene polymer,including those produced in high pressure, gas phase, and/or slurryprocesses. In a preferred embodiment, the blends include at least 0.1 wt% and up to 99.9 wt % of the branched modifier polymer and at least 0.1wt % and up to 99.9 wt % of the ethylene polymer, with these weightpercents based on the total weight of the blend. Alternative lowerlimits of the branched modifier polymer can be 1%, 5%, 10%, 20%, 30%, or40% by weight. Alternative upper limits of the branched modifier polymercan be 95%, 90%, 80%, 70%, or 60% by weight. Ranges from any lower limitto any upper limit are within the scope of the invention. Preferredblends include from 1 wt % to 85 wt %, alternatively from 2 wt % to 50wt % or from 3 wt % to 30 wt % of the branched modifier polymer. In oneembodiment, the balance of the weight percentage is the weight of theethylene polymer component.

In one preferred embodiment, the polymer blend includes ametallocene-catalyzed branched modifier comprising units derived fromethylene, one or more C₄ to C₂₀ α-olefin comonomers and a polyene withat least two polymerizable bonds. The branched modifier has a comonomer(α-olefin+polyene) content of from about 2 wt % to about 20 wt % (basedupon the weight of the copolymer), a composition distribution breadthindex of at least 60%, a melt index (ASTM 1238, 190° C., 2.16 kg) of 15dg/min or less, a density of from about 0.850 to about 0.980 g/cm³(preferably from about 0.890 to about 0.980 g/cm³), and a molecularweight distribution (Mw/Mn) of from about 2.5 to about 40.

In another preferred embodiment, the polymer blends include branchedpolyethylene modifier comprising units derived from ethylene andpolyenes.

In a preferred embodiment, this invention comprises a blend comprising:

a) any branched modifier described herein present at from 0.1 wt % to99.5 wt %, (preferably 0.5 wt % to 20 wt %, preferably 0.75 wt % to 10wt %, preferably 0.9 wt % to 5 wt %, preferably 1 wt % to 3 wt %,preferably 1 wt % to 2 wt %); and

b) ethylene polymer having a g′_(vis) of 0.97 or more, a CDBI of 60% ormore and a density of 0.90 g/cc or more, wherein the ethylene polymerhas a g′_(vis) of at least 0.01 units higher than the g′_(vis) of thebranched modifier (preferably at least 0.02, preferably at least 0.03,preferably 0.04, preferably at least 0.05, preferably at least 0.1,preferably at least 0.2, preferably at least 0.3, preferably at least0.4, preferably at least 0.5 units higher), preferably the ethylenepolymer is present at from 99.9 wt % to 0.5 wt %, preferably 99.5 wt %to 80 wt %, preferably 99.25 wt % to 90 wt %, preferably 99.1 wt % to 95wt %, preferably 99 wt % to 97 wt %, preferably 99 wt % to 98 wt %).

Preferably, the ethylene copolymer comprises at least 50 wt % ethylene,and has up to 50 wt %, preferably 1 wt % to 35 wt %, even morepreferably 1 wt % to 6 wt % of a C₃ to C₂₀ comonomer (preferably hexeneor octene), based upon the weight of the copolymer. The polyethylenecopolymers preferably have a composition distribution breadth index(CDBI) of 60% or more, preferably 60% to 80%, preferably 65% to 80%. Inanother preferred embodiment, the ethylene copolymer has a density of0.910 to 0.950 g/cm³ (preferably 0.915 to 0.940 g/cm³, preferably 0.918to 0.925 g/cm³) and a CDBI of 60% to 80%, preferably between 65% and80%. Preferably, these polymers are metallocene polyethylenes (mPEs).

In another embodiment, the ethylene copolymer comprises mPEs describedin U.S. Publication No. 2007/0260016 and U.S. Pat. No. 6,476,171, e.g.copolymers of an ethylene and at least one alpha olefin having at least5 carbon atoms obtainable by a continuous gas phase polymerization usingsupported catalyst of an activated molecularly discrete catalyst in thesubstantial absence of an aluminum alkyl based scavenger (e.g.triethylaluminum, trimethylaluminum, tri-isobutyl aluminum,tri-n-hexylaluminum, and the like), which the polymer has a Melt Indexof from 0.1 to 15 (ASTM D 1238, condition E); a CDBI of at least 70%, adensity of from 0.910 to 0.930 g/cc; a Haze (ASTM D1003) value of lessthan 20; a Melt Index ratio (121/12, ASTMD 1238) of from 35 to 80; anaveraged Modulus (M) (as defined in U.S. Pat. No. 6,255,426) of from20,000 to 60,000 psi (13790 to 41369 N/cm²) and a relation between M andthe Dart Impact Strength (26 inch, ASTM D 1709) in g/mil (DIS) complyingwith the formula:

DIS≦0.8×[100+e ^((11.71−0.000268×M+2.183×10) ⁻⁹ ^(×M) ² ^()]),

where “e” represents 2.1783, the base Napierian logarithm, M is theaveraged Modulus in psi and DIS is the 26 inch (66 cm) dart impactstrength.

In another preferred embodiment, the polymer blend includes ametallocene-catalyzed branched modifier copolymer comprising unitsderived from ethylene and one or more C₄ to C₂₀ α-olefin comonomers. Thebranched modifier has a comonomer content of from about 2 wt % to about20 wt %, a composition distribution breadth index (CDBI) of at least60%, a melt index (MI or 12) of 1.0 dg/min or less and a branching indexof g′_(vis) of less than 0.97, preferably 0.96 or less, more preferably0.94 or less, wherein the ethylene polymer has a g′_(vis) of at least0.01 units higher than the g′_(vis) of the branched modifier.

In another embodiment, the difference in density of the branchedmodifier and ethylene polymer is 0.04 g/cm³ or less, preferably 0.02g/cm³ or less. In another embodiment, the difference in density of thebranched modifier and ethylene polymer is 0.03 g/cm³ or more, preferably0.05 g/cm³ or more, preferably 0.08 g/cm³ or more, preferably 0.10 g/cm³or more, preferably 0.20 g/cm³ or more.

In another embodiment, the difference in melt flow index (190° C., 2.16kg) of the branched modifier and the ethylene polymer is 10 dg/min orless, preferably 5 dg/min or less.

In one embodiment, the ratio of the complex viscosity of the branchedmodifier to the complex viscosity of the ethylene polymer component inthe blend composition is at least 0.1:1 (preferably at 0.04:1). Thecomplex viscosity is measured at a frequency of 0.1 rad/sec and atemperature of 190° C. according to procedure described in the TestMethods section below.

In an alternative embodiment, the MI (190° C., 2.16 kg) of the branchedmodifier is 90% or less of the MI of the ethylene polymer component,preferably 80% or less, preferably 70% or less.

In an alternative embodiment, the complex viscosity at 0.1 rad/sec ofthe modifier is equal to or greater than the complex viscosity at 0.1rad/sec of the ethylene polymer prior to combination with the branchedmodifier.

In an alternative embodiment, the complex viscosity at 0.1 sec⁻¹ of thebranched polyethylene modifier is at least 320% greater than (preferably2000% greater than) the complex viscosity at 0.1.

In another embodiment, the polyethylene/modifier compositions of thisinvention comprise less than 50 wt % (preferably less than 40 wt %,preferably less than 30 wt %, preferably less than 20 wt %, preferablyless than 10 wt %, more preferably less than 5 wt %, more preferablyless than 1 wt %) propylene homopolymer or copolymer, based upon theweight of the composition, where a propylene homopolymer or copolymer isa polymer comprising at least 50 mol % propylene monomer units.

In another embodiment, the polyethylene/modifier compositions of thisinvention comprise less than 50 wt % (preferably less than 40 wt %,preferably less than 30 wt %, preferably less than 20 wt %, preferablyless than 10 wt %, more preferably less than 5 wt %, more preferablyless than 1 wt %) of EP Rubber, based upon the total weight of thecomposition. For purposes of this invention and the claims thereto, an“EP Rubber” is defined to be a copolymer of ethylene and propylene, andoptionally diene monomer(s), chemically crosslinked (i.e. cured) or not,where the ethylene content is from 35 wt % to 80 wt %, the diene contentis 0 wt % to 15 wt %, and the balance is propylene; and where thecopolymer has a Mooney viscosity, ML(1+4) @125° C. (measured accordingto ASTM D1646) of 15 to 100. For purposes of this invention and theclaims thereto, an “EPDM” or “EPDM Rubber” is defined to be an EP Rubberhaving diene present.

In a preferred embodiment, the polyethylene compositions comprising oneor more ethylene polymers and one or more branched modifiers showcharacteristics of strain hardening in extensional viscosity. Strainhardening is observed as a sudden, abrupt upswing of the extensionalviscosity in the transient extensional viscosity vs. time plot. Thisabrupt upswing, away from the behavior of a linear viscoelasticmaterial, was reported in the 1960s for LDPE (reference: J. Meissner,Rheology Acta., Vol. 8, p. 78, 1969) and was attributed to the presenceof long branches in the polymer. In one embodiment, the inventivepolyethylene compositions have strain-hardening in extensionalviscosity. The strain-hardening ratio (SHR) is 1.1 or more for theinventive polyethylene compositions, preferably at least 1.5 or more,preferably 2.0 or more, preferably 2.5 or more, preferably 4 or more,more preferably 6 or more, and even more preferably 8 or more when theextensional viscosity is measured at a strain rate of 1 sec⁻¹ and at atemperature of 150° C.

In another embodiment of the invention the SHR of the blend is at least10% higher than the SHR of the linear polyethylene used in the blend,preferably at least 20% higher, at least 30% higher, at least 50%higher, at least 100% higher, at least 500% higher, at least 800%higher, at least 1000% higher.

In one embodiment, the melt strength of inventive polyethylenecomposition is at least 5% higher than the melt strength of ethylenepolymer component used in the blend (preferably at least 10%, preferablyat least 20%, preferably at least 30%, preferably at least 40%,preferably at least 50%, preferably at least 60%, preferably at least100%, preferably at least 200%, preferably at least 300%, preferably atleast 400%, preferably at least 500%, preferably at least 600%,preferably at least 700%, preferably at least 800%).

In a preferred embodiment of the invention, the linear polyethylene ispresent in the blend at from 80 to 99.5 wt % (preferably 99.5 wt % to 90wt %, preferably 99.25 wt % to 95 wt %, preferably 99 wt % to 95 wt %,preferably 99 wt % to 97 wt %, preferably 99 wt % to 98 wt %) and thebranched modifier is present in the blend at from 0.5 to 20 wt %(preferably 0.5 wt % to 10 wt %, preferably 0.75 wt % to 5 wt %,preferably 1 wt % to 5 wt %, preferably 1 wt % to 3 wt %, preferably 1wt % to 2 wt %), based upon the weight of the blend, and the meltstrength of the blend is at least 5% higher than the melt strength oflinear ethylene polymer component used in the blend (preferably at least10%, preferably at least 20%, preferably at least 30%, preferably atleast 40%, preferably at least 50%, preferably at least 100%, preferablyat least 200%, preferably at least 300%, preferably at least 400%,preferably at least 500%, preferably at least 600%, preferably at least700%, preferably at least 800%).

In a preferred embodiment, the composition has a melt strength at least500% higher than the melt strength of the polyethylene prior tocombination with the branched polyethylene modifier, preferably at least600%, preferably at least 700%, preferably at least 800% higher.

Shear rheology of the inventive composition can be different from therheology of the ethylene polymer component, depending on the propertiesof the branched modifier polymer. In one embodiment, the difference incomplex viscosity between the inventive composition and ethylene polymercomponent is less than 10%, preferably less than 5% at all frequencies.

In another embodiment of the invention, the complex viscosity of theinventive polyethylene composition is at least 30% higher than thecomplex viscosity of the ethylene polymer component employed in theblend composition when the complex viscosity is measured at a frequencyof 0.1 rad/sec and a temperature of 190° C., and the complex viscosityof the inventive polyethylene composition is the same or less than thecomplex viscosity of the ethylene polymer component used in the blendcomposition when the complex viscosity is measured at a frequency of 100rad/sec and a temperature of 190° C. Complex viscosity is measuredaccording to procedure described in the Test Methods section below.Alternatively, the shear thinning ratio of the inventive composition isat least 10% higher than the shear thinning ratio of the ethylenepolymer component.

In one embodiment, crystallization temperature, Tc, (as determined byDSC as described in the Test Methods section below) of the branchedmodifier polymer is lower than the Tc of the ethylene polymer.Preferably, the Tc of the polyethylene composition is lower than the Tcof the ethylene polymer component by at least 2° C., preferably by atleast 5° C.

In another embodiment, Tc of the branched modifier polymer is higherthan the Tc of the ethylene polymer component in the blend; preferablythe Tc of the polyethylene composition is higher than the Tc of theethylene polymer component by at least 2° C., preferably by at least 5°C.

Preferably, the blend of the polyethylene and the branched modifier hasa melt index, as measured by ASTM D-1238 at 190° C. and 2.16 kg (alsoreferred to as 12) of up to 30 dg/min, alternately 0.1 to 25 dg/min,alternately 0.2 to than 20 dg/min, alternately less than 0.5 to 10dg/min.

Preferably, the HLMI (ASTM D 1238 190° C., 21.6 kg, also referred to as121) of the blend of the polyethylene and the modifier is 10.0 dg/min orless, preferably 5 dg/min or less, preferably 1 dg/min or less.

Branched Modifiers

The polyethylene compositions of the present invention include abranched modifier (also referred to as a “modifier”, or a “branchedpolyethylene modifier” or a “branched modifier polymer” herein). It willbe realized that the classes of materials described herein that areuseful as modifiers can be utilized alone or admixed with othermodifiers described herein in order to obtain desired properties.

In one embodiment, the branched modifier useful herein is a long chainbranched polyethylene copolymer comprising units derived from at leastone polymerizable polyene.

Polymerizable polyene is a polyene with at least two double bonds thatcan be incorporated into growing polyethylene chains during apolymerization reaction. In a preferred embodiment, the branchedmodifier is a terpolymer of 1) ethylene; 2) up to 20 mol % (preferablyfrom 0.1 mol % to 15 mol %, preferably from 1 mol % to 10 mol %) of oneor more C₄ to C₄₀ (preferably C₄ to C₂₀, preferably C₆ to C₁₂) olefins,preferably alpha olefins (preferably 1-butene, 1-hexene, and 1-octene);and 3) one or more polymerizable polyenes (preferably present at 5 mol %or less, preferably 1 mol % or less, more preferably 0.5 mol % or less,alternately the polyene is present at 0.001 mol % to 5 mol %,alternately 0.01 mol % to 3 mol %, alternately 0.1 mol % to 1 mol %),preferably alpha-omega dienes, preferably one or more of 1,4-pentadiene,1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene,1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene,and 1,13-tetradecadiene, tetrahydroindene, norbomadiene also known asbicyclo-(2.2.1)-hepta-2,5-diene, dicyclopentadiene, 5-vinyl-2-norbomene,1,4-cyclohexadiene, 1,5-cyclooctadiene, and 1,7-cyclododecadiene.

Long chain branched modifier polymers can be obtained when a polymerchain (also referred as macromonomer) with reactive polymerizable groupsis incorporated into another polymer chain during the polymerization ofthe latter. The resulting product comprises a backbone of the secondpolymer chain with branches of the first polymer chains (i.e.macromonomer) extending from the backbone. For polymerization withpresence of polymerizable polyene (normally a diene), the polyene can beincorporated into a polymer chain through one polymerizable double bondin a similar manner as the incorporation of other comonomers such as1-hexene and 1-octene. Polymer chains containing polymerizable polyenethus become reactive due to the residual second polymerizable doublebond of polyene. These reactive polymer chains can then be incorporatedinto another growing polymer chain during polymerization through thesecond double bond of a polyene. This doubly inserted polyene creates alinkage between two polymer chains and leads to branched structures. Thebranching structure formed through diene linkage between polymer chainsis referred to as “H” type and is preferably a tetra-functionalbranching structure. The number of branches and level of branches(branches on branches) depend on the amount of polyene incorporated.

Polyene incorporation in polymerization is often catalyst specific. Forpolymerization with metallocene catalysts, examples of usefulpolymerizable polyenes include butadiene, 1,4-pentadiene, 1,5-hexadiene,1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene,1,13-tetradecadiene, tetrahydroindene, norbomadiene also known asbicyclo-(2.2.1)-hepta-2,5-diene, dicyclopentadiene, 5-vinyl-2-norbomene,1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,7-cyclododecadiene, and vinylcyclohexene.

In a polymerization system with a metallocene catalyst, a macromonomerwith reactive double bonds can also be incorporated into another polymerchain to form a long chain branching polymer with tri-functionalbranching structures. These reactive double bonds can be vinyl groups onthe chain ends of polymer chains produced in the polymerization system.The resulting product comprises a backbone of the second polymer chainwith branches of the first polymer chains extending from the backbone.In one embodiment, the long chain branched modifier includes bothtetra-functional and tri-functional branching structures.

In a further aspect, the modifiers comprise at least 80 mol % ofethylene and from 0.01 mol % to 10 mol % of at least one diene selectedfrom the group consisting of norbomadiene, 5-vinyl-2-norbomene, C₆ toC₁₂ α,ω-dienes, and mixtures thereof with the balance being analpha-olefin selected from the group consisting of propylene, butene,pentene, hexene, octene, and mixtures thereof.

Long chain branching structure of the modifiers can be detected usingGPC-3D as described in the Test Methods section below. A branching indexg′_(vis) is used to measure the level of branching. In one embodiment,the branched modifier polymer has a g′_(vis) of less than 0.70,preferably 0.65 or less, more preferably 0.60 or less, preferably 0.55or less, even more preferably 0.50 or less.

For ethylene copolymers with α,ω-dienes, propylene, and 1-butene thepresence of long chain branched structures in the branched modifier canbe detected using nuclear magnetic resonance spectroscopy (NMR). In¹³C-NMR, the modifiers are dissolved in tetrachloroethane-d2 at 140° C.and the spectra are collected at 125° C. Assignments of peaks forethylene/propylene, ethylene/butene, ethylene/hexene, andethylene/octene copolymers have been reviewed by James C. Randall inPolymer Reviews, 29 (2), p. 201-317, (1989). Assignments forpropylene/butene, propylene/pentene, propylene/hexene,propylene/heptene, and propylene/octene are presented by U. M Wahner, etal., (Macromol. Chem. Phys. 2003, 204, p. 1738-1748). These assignmentswere made using hexamethyldisiloxane as the internal standard. Toconvert them to the same standard used in the other references add 2.0to the chemical shifts. Assignments and a method of measuring deceneconcentration have been reported for propylene/ethylene/deceneterpolymers in Escher, Galland, and Ferreira (J. Poly. Sci., Part A:Poly. Chem., 41, p. 2531-2541 (2003)) and Ferreira, Galland, Damiani,and Villar (J. Poly. Sci, Part A: Poly. Chem, 39, p. 2005-2018, (2001)).The peaks in the ¹³C-NMR spectrum of ethylene/norbornadiene copolymersare assigned by Monkkonen and Pakkanen (Macromol. Chem. Phys., 200, p.2623-2628 (1999)) and Radhakrishnan and Sivaram (Macromol. Chem. Phys.,200, p. 858-862 (1999).

In one embodiment, ethylene and optional comonomers, and α,ω-dienes areused in the synthesis of the branched modifier, in which the α,ω-dieneshave their double bonds inserted into ethylene copolymer chains. In oneembodiment, ethylene propylene, 1-butene and α,ω-dienes are used in thesynthesis of the branched modifier, in which the α,ω-dienes have theirdouble bonds inserted into ethylene copolymer chains. The numbers ofα,ω-dienes inserted into each of these polymer backbones can bequantified in the ¹³C-NMR spectra using the assignments cited forethylene/octene, propylene/octene, or propylene/ethylene/decenecopolymers. The chemical shifts of the methines at the diene insertionsites, carbons adjacent to the methines on the backbones, and carbons ato the methines on the octene or decene will be unchanged when appliedto copolymers containing C₈-C₁₂ α,ω-dienes, because the residual doublebonds or second polymer chains at the ends of the α,ω-dienes are too faraway (4 or more carbons) to change the shifts.

The following procedure can be used to calculate the diene branches per10,000 carbons (B):

(a) Integrate the area under the vinyl allylic carbon peak at 33.91 ppm(V).

(b) Integrate the area of the aliphatic region (10-50 ppm) of the¹³C-NMR spectrum (Ali). Do not include the area of the vinyl allylicpeak.

(c) Calculate the total number of carbons in the spectrum, Tot, bysumming the area of the aliphatic region and two times the area undervinyl allylic peak, i.e. Tot=Ali+2*V.

(d) Average the areas of the peaks assigned to the inserted ends of theα,ω-dienes to calculate the number of inserted diene ends (D).

(e) Estimate the number of diene branches, B, as 0.5*(D−V). Thisestimate may be slightly low, because some of the vinyl groups in theallylic vinyl peak may have been from chain ends. However, typically,the number of residual vinyl groups in the dienes is much larger thanthose at the chain ends, because there are many dienes inserted perchain.

(f) To convert to diene-branches per 10,000 carbons, divide B by thetotal number of carbons, Tot, and multiply by 10,000.

In other embodiments, copolymers of ethylene and norbomadiene are usedto synthesize the branched modifier. The singly inserted norbomadienescan be quantified by integrating the peak for the bridging methylene,C7, at 42.7 to 43.5 ppm. When both double bonds have inserted, thebridging methylene is called BC7 and is found at 33.8 to 35.0 ppm. Tocalculate the norbomadiene branches per 10000 carbons, the area underthe peak at 33.8 to 35.0 is multiplied by 10000 and divided by the totalaliphatic area from 10 to 50 ppm. Because the bridging methylene is 3 toboth of the double bonds of norbomadiene, it shifts after one doublebond inserts and shifts again after the second double bond inserts.However, it is 4 carbons away from possible substituents at the 3positions to the norbomene ring. These substituents produce very weakchanges in the absorptions and these integration ranges can be used forall the norbomadiene-containing polymers described herein.

Branched structures can also be observed by Small Amplitude OscillatoryShear (SAOS) measurement of the molten polymer performed on a dynamic(oscillatory) rotational rheometer. From the data generated by such atest it is possible to determine the phase or loss angle δ, which is theinverse tangent of the ratio of G″ (the loss modulus) to G′ (the storagemodulus). For a typical linear polymer, the loss angle at lowfrequencies (or long times) approaches 90 degrees, because the chainscan relax in the melt, adsorbing energy, and making the loss modulusmuch larger than the storage modulus. As frequencies increase, more ofthe chains relax too slowly to absorb energy during the oscillations,and the storage modulus grows relative to the loss modulus. Eventually,the storage and loss moduli become equal and the loss angle reaches 45degrees. In contrast, a branched chain polymer relaxes very slowly,because the branches need to retract first before the chain backbone canrelax along its tube in the melt. This polymer never reaches a statewhere all its chains can relax during an oscillation, and the loss anglenever reaches 90 degrees even at the lowest frequency, w, of theexperiments. The loss angle is also relatively independent of thefrequency of the oscillations in the SAOS experiment; another indicationthat the chains can not relax on these timescales.

As known by one of skill in the art, rheological data may be presentedby plotting the phase angle versus the absolute value of the complexshear modulus (G*) to produce a van Gurp-Palmen plot. The plot ofconventional polyethylene polymers shows monotonic behavior and anegative slope toward higher G* values. Conventional LLDPE polymerwithout long chain branches exhibit a negative slope on the vanGurp-Palmen plot. For branched modifiers, the phase angels shift to alower value as compared with the phase angle of a conventional ethylenepolymer without long chain branches at the same value of G*. The vanGurp-Palmen plots of some embodiments of the branched modifier polymersdescribed in the present disclosure exhibit two slopes—a positive slopeat lower G* values and a negative slope at higher G* values.

In a plot of the phase angle δ versus the measurement frequency ω,polymers that have long chain branches exhibit a plateau in the functionof δ(ω), whereas linear polymers do not have such a plateau. Accordingto Garcia-Franco et al. (Macromolecules 2001, 34, No. 10, p. 3115-3117),the plateau in the aforementioned plot will shift to lower phase anglesδ when the amount of long chain branching occurring in the polymersample increases. Dividing the phase angle at which the plateau occursby a phase angle of 90°, one obtains the critical relaxation exponent n,which can then be used to calculate a gel stiffness using the equation:

η*(ω)=S(1−n)ω^(n−1)

wherein η* represents the complex viscosity (Pa·s), w represents thefrequency, S is the gel stiffness, Γ is the gamma function (see Beyer,W. H. Ed., CRC Handbook of Mathematical Sciences 5^(th) Ed., CRC Press,Boca Rotan, 1978) and n is the critical relaxation exponent.

Polymer modifiers produced herein preferably have a gel stiffness ofmore than 150 Pa·s, preferably at least 300 Pa·s, and more preferably atleast 500 Pa·s. The gel stiffness is determined at the test temperatureof 190° C. A preferred critical relaxation exponent n for the polymermodifiers produced herein is less than 1 and more than 0, generally, nwill be between 0.1 and 0.92, preferably between 0.2 and 0.85.

Small amplitude oscillatory shear data can be transformed into discreterelaxation spectra using the procedure on p. 273-275 in R. B. Bird, R.C. Armstrong, and O. Hassager, Dynamics of Polymeric Liquids, Volume 1,Fluid Mechanics, 2^(nd) Edition, John Wiley and Sons, (1987). Thestorage and loss moduli are simultaneously least squares fit with thefunctions,

G′(ω_(j))=Ση_(k)λ_(k)ω_(j) ²/(1+(η_(k)ω_(k))²)

G″(ω_(j))=Ση_(k)λ_(k)ω_(j)/(1+(η_(k)ω_(k))²)

at the relaxation times λ_(k)=0.01, 0.1, 1, 10, and 100 seconds. Thesums are from k=1 to k=5. The sum of the η_(k)'s is equal to the zeroshear viscosity, η₀. An indication of high levels of branched blockproducts is a high value of η₅, corresponding to the relaxation time of100 s, relative to the zero shear viscosity. The viscosity fraction ofthe 100 s relaxation time is η₅ divided by the zero shear viscosity, η₀.For the modifiers of this invention the viscosity fraction of the 100second relaxation time is preferably at least 0.1, more preferably 0.4,and most preferably 0.8. In contrast, viscosity fractions of 100 secondchains of conventional isotactic polypropylene are of the order of 0.10or less and of conventional propylene/ethylene copolymers are of theorder of 0.10 or less. Chains with long relaxation times can not relaxduring the cycle time of the small amplitude oscillatory shearexperiment and lead to high zero shear viscosities.

The branched modifiers used herein preferably have good shear thinning.Shear thinning is characterized by the decrease of the complex viscositywith increasing shear rate.

One way to quantify the shear thinning is to use a ratio of complexviscosity at a frequency of 0.1 rad/s to the complex viscosity at afrequency of 100 rad/s (referred to as the shear thinning ratio or thecomplex viscosity ratio). Preferably, the complex viscosity ratio of anymodifier produced herein is 100 or more, preferably 120 or more,preferably 130 or more, preferably 140 or more, preferably 150 or more,when the complex viscosity is measured at 190° C.

Shear thinning can be also characterized using a shear thinning index.The term “shear thinning index” is determined using plots of thelogarithm (base ten) of the dynamic viscosity versus logarithm (baseten) of the frequency. The slope is the difference in the log (dynamicviscosity) at a frequency of 100 rad/s and the log (dynamic viscosity)at a frequency of 0.01 rad/s divided by 4. These plots are the typicaloutput of small amplitude oscillatory shear (SAOS) experiments. Forpurposes of this invention, the SAOS test temperature is 190° C. forethylene polymers. Polymer viscosity is conveniently measured inPascal·seconds (Pa·s) at shear rates within a range of from 0.01 to 398rad/sec and at 190° C. under a nitrogen atmosphere using a dynamicmechanical spectrometer, such as the Advanced Rheometrics ExpansionSystem (ARES). Generally a low value of shear thinning index indicatesthat the polymer is highly shear-thinning and that it is readilyprocessable in high shear processes, for example by injection molding.The more negative this slope, the faster the dynamic viscosity decreasesas the frequency increases. Preferably, the modifier has a shearthinning index of less than −0.2, preferably −0.4 or less, preferably−0.6 or less. These types of modifiers are easily processed in highshear rate fabrication methods, such as injection molding.

The branched modifier described herein also preferably hascharacteristics of strain hardening in extensional viscosity. Animportant feature that can be obtained from extensional viscositymeasurements is the attribute of strain hardening in the molten state.

Strain hardening is observed as a sudden, abrupt upswing of theextensional viscosity in the transient extensional viscosity vs. timeplot. This abrupt upswing, away from the behavior of a linearviscoelastic material, was reported in the 1960s for LDPE (reference: J.Meissner, Rheol. Acta., Vol. 8, p. 78, 1969) and was attributed to thepresence of long branches in the polymer. The strain-hardening ratio(SHR) is defined as the ratio of the maximum transient extensionalviscosity over three times the value of the transient zero-shear-rateviscosity at the same strain rate. Strain hardening is present in thematerial when the ratio is greater than 1. In one embodiment, thebranched modifiers have strain-hardening in extensional viscosity.Preferably the strain-hardening ratio of the branched modifier is 2 orgreater, preferably 5 or greater, more preferably 10 or greater, andeven more preferably 15 or greater when extensional viscosity ismeasured at a strain rate of 1 sec⁻¹ and at a temperature of 150° C.

The branched modifiers of this invention generally exhibit melt strengthvalues greater than that of conventional linear or long chain branchedpolyethylene of similar melt index. As used herein “melt strength”refers to the force required to draw a molten polymer extrudate at arate of 12 mm/s² at an extrusion temperature of 190° C. until breakageof the extrudate, whereby the force is applied by take up rollers. Inone embodiment, the melt strength of the branched modifier polymers isat least 20% higher than that of a linear polyethylene with the samedensity and MI. Preferably, any modifier produced herein has a meltstrength of at least 10 cN, preferably at least 15 cN, preferably atleast 20 cN, preferably at least 25 cN, preferably at least 30 cN.

The branched modifiers preferably have a density in a range of from0.840 g/cm³ to 0.960 g/cm³ in one embodiment, from 0.850 g/cm³ to 0.95g/cm³ in a more particular embodiment, from 0.850 g/cm³ to 0.920 g/cm³in yet a more particular embodiment, from 0.860 g/cm³ to 0.930 g/cm³ inyet a more particular embodiment, from 0.870 g/cm³ to 0.92 g/cm³ in yeta more particular embodiment, less than 0.925 g/cm³ in yet a moreparticular embodiment, less than 0.920 g/cm³ in yet a more particularembodiment, and less than 0.900 g/cm³ in yet a more particularembodiment.

When produced in a gas-phase or a slurry process, the branched modifiersof the invention have a bulk density of from 0.400 to 0.900 g/cm³ in oneembodiment, and from 0.420 to 0.800 g/cm³ in another embodiment, andfrom 0.430 to 0.500 g/cm³ in yet another embodiment, and from 0.440 to0.60 g/cm³ in yet another embodiment, wherein a desirable range maycomprise any upper bulk density limit with any lower bulk density limitdescribed herein.

In a preferred embodiment, the branched modifier has a strain hardeningratio of 5 or more, preferably 10 or more, preferably 20 or more,preferably 30 or more, preferably 40 or more, preferably 50 or more;and/or an Mw of 100,000 g/mol or more, preferably from 100,000 to2,000,000 g/mol, alternately from 200,000 to 1,000,000 g/mol,alternately from 150,000 to 750,000 g/mol.

Preferably, the HLMI (ASTM D 1238 190° C., 21.6 kg) of the modifier is1.0 dg/min or less, preferably 0.5 dg/min or less. HLMI is also referredas to 121.

The branched modifier of the invention preferably has an Mw of 100,000to 2,000,000 g/mol, preferably 150,000 to 1,000,000, more preferably200,000 to 500,000, as measured by size exclusion chromatography, asdescribed in the Test Methods section below, and/or an M_(w)/M_(n) of 2to 40, preferably 2.5 to 30, more preferably 3 to 20, more preferably 3to 25 as measured by size exclusion chromatography, and/or a M_(z)/M_(w)of 2 to 50, preferably 2.5 to 30, more preferably 3 to 20, morepreferably 3 to 25. The Mw referred to herein and for purposes of theclaims attached hereto is obtained from GPC using a light scatteringdetector as described in the Test Methods section below.

The branched modifier of the invention preferably has a density of 0.85to 0.97 g/cm³, preferably 0.86 to 0.965 g/cm³, preferably 0.88 to 0.96g/cm³, alternatively between 0.860 and 0.910 g/cm³, alternativelybetween 0.910 and 0.940 g/cm³, or alternatively between 0.94 to 0.965g/cm³ (determined according to ASTM D 1505 using a density-gradientcolumn on a compression-molded specimen that has been slowly cooled toroom temperature (i.e. over a period of 10 minutes or more) and allowedto age for a sufficient time that the density is constant within+/−0.001 g/cm³).

In a preferred embodiment, any branched modifier described herein has ag′_((Z ave)) of 0.80 or less, preferably 0.75 or less, preferably 0.70or less, preferably 0.65 or less, preferably 0.60 or less, preferably0.55 or less, preferably 0.50 or less, preferably 0.45 or less,preferably 0.40 or less, preferably 0.35 or less.

Z average branching index (g′_((Z ave))) is determined using datagenerated using the SEC-DRI-LS-VIS procedure described in the TestMethods section below, paragraph [0334] to [0341], p. 24-25 of U.S.Publication No. 2006/0173123 (including the references cited therein,except that the GPC procedure is run as described in the Test Methodssection below), where

$g_{Zave}^{\prime} = \frac{\Sigma \; {C_{i}\left\lbrack \eta_{i} \right\rbrack}_{b}}{\Sigma \; C_{i}{KM}_{i}^{\alpha}}$

where [η_(i)]_(b) is the viscosity of the polymer in slice i of thepolymer peak, and M_(i) is the weight averaged molecular weight in slicei of the polymer peak measured by light scattering, K and α are theparameters for linear polyethylene (K=0.000579 and α=0.695), C₁=polymerconcentration in the slice i in the polymer peak times the mass of theslice squared, M_(i) ².

In any embodiment of the invention described herein, the branchedmodifier may have a complex viscosity at 0.1 rad/sec and a temperatureof 190° C. of at least 130,000 Pa·s (preferably at least 150,000 Pa·s,preferably at least 200,000 Pa·s, preferably at least 500,000 Pa·s,preferably from 130,000 to 1,000,000 Pa·s).

In any embodiment of the invention described herein, the branchedmodifier may have a phase angle of 25 degrees or less. Alternatively,any branched modifier may have a phase angle at a complex shear modulusof 100,000 Pascal of 30 degrees or less, preferably 28 degrees or less,more preferably 25 degrees or less. The shear rheology is measured at190° C. according to the procedure described in the Example section.

In any embodiment of the invention described herein, the branchedpolyethylene modifier preferably has a complex viscosity of greater than300% of the complex viscosity of the ethylene polymer (preferablygreater than 350%, preferably greater than 400%, preferably greater than500%, preferably greater than 600%, preferably greater than 700%). Thecomplex viscosity is measured at a frequency of 0.1 rad/sec and atemperature of 190° C.

In any embodiment of the invention described herein, the branchedpolyethylene modifier preferably has a phase angle at complex shearmodulus G*=100,000 Pa of less than 40°, preferably less than 35°,preferably less than 30°, preferably less than 28°, preferably less than27°, preferably less than 26°, preferably less than 25°, preferably lessthan 24°, preferably less than 23°, preferably less than 22°, asmeasured at 190° C.

Polymerization Processes to Produce Modifiers

The modifiers described herein may be produced using catalyst andactivator as described below in a high pressure, solution, gas or slurrypolymerization process or a combination thereof, preferably solutionphase or gas phase polymerization process. In a preferred embodiment,the diene is present in the monomer feed at a feed concentration of 2 to5000 ppm, preferably 10 to 3000, more preferably 20 to 2000 ppm. Thediene concentration is calculated based on the total weight of allmonomer and comonomer in the feed.

The inventive polyethylene composition comprises a branched modifier,which typically is an ethylene co- or ter-polymer polymer, whichpreferably comprises at least one polymerizable diene. The main functionof diene is to create linkages between polymer chains and thus producelong chain branched structures. The content of diene in the branchedmodifier is typically high enough to create high levels of branching fordesired applications and low enough to produce gel-free product.Gel-free products can be obtained by controlling the diene types and itsconcentrations, by controlling monomer concentration and amount ofpolymer synthesized (polymer loading), or by adding H₂ or other chaintransfer agents. Chain transfer agents lower the molecular weights ofthe polymers synthesized in the reactor. Increasing the total monomerconcentration relative to the diene concentration makes the relativeconcentrations of dienes lower and a lower fraction of dienes willincorporate into each polymer chain. Higher total monomer concentrationsalso increase the molecular weights of the chains for most catalystsystems. Since the number of dienes incorporated per chain depends onthe molecular weight or length of the chains, the addition of H₂ orchain transfer agents also affects the number of sites per chainavailable to form diene bridges during the polymerization.

Preferably the diene component is a straight chain diene, such as1,7-octadiene or 1,9-decadiene, or is a cyclic diene, such as vinylnorbomene or norbomadiene. One particularly useful diene is norbomadienebecause both of its double bonds are more reactive than α-olefins in ametallocene catalyzed system. Thus, norbomadiene is easy to incorporateinto the polymer, leading to much higher concentrations of long chainbranched products.

In polymerization systems with metallocene catalysts, a macromonomerwith reactive double bonds can also be incorporated into another polymerchain(s) to form a long chain branching polymer with tri-functionalbranching structures. These reactive double bonds can be vinyl groups onthe chain ends of polymer chains produced in the polymerization system.

Proper selection of catalyst and process conditions can enhance theproduction of vinyl chain end macromonomers, and thus increase the levelof long chain branching. In such system, lower diene concentration inthe reactor is required to produce branched modifiers with same level ofbranching. Process operability might be also improved since low levelsof diene concentration will greatly reduce the potential of gelformation in reactor. In one embodiment, the polymerization processincludes a reactor system which can produce ethylene polymer(macromonomer) having reactive end groups, such as vinyl end groups.

Generally, it is desirable that the macromonomers derived from thesystem have at least 50%, such as at least 70% of vinyl terminalunsaturations based on the total unsaturated olefin chain ends.Unsaturated chain ends (and percents thereof) are determined usingproton NMR (collection at 120° C., 400 MHz) as described in U.S.Publication No. 2009/0318644 (U.S. application Ser. No. 12/143,663,filed Jun. 20, 2008), particularly the procedure described on p. 33 line25 to p. 34, line 11, of the application as filed. Combination of asystem capable of producing reactive macromonomer with a polymerizablediene can be an efficient method to produce the branched modifiers.

In one embodiment, this invention is directed toward the solution, bulk,slurry or gas phase polymerization reactions involving thepolymerization of ethylene and one or more comonomers having from 3 to40 carbon atoms, preferably 4 to 20 carbon atoms, and more preferably 6to 8 carbon atoms, and one or more polymerizable dienes. Preferredcomonomers include one or more of propylene, butene-1, pentene-1,4-methyl-pentene-1, hexene-1, octene-1, decene-1, 3-methyl-pentene-1,and cyclic olefins or a combination thereof. Preferred polymerizabledienes include diolefins such as butadiene, α-ω diene such as1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene,1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene,1,12-tridecadiene, and 1,13-tetradecadiene; tetrahydroindene;norbomadiene also known as bicyclo-(2.2.1)-hepta-2,5-diene;dicyclopentadiene; 5-vinyl-2-norbomene; 1,4-cyclohexadiene;1,5-cyclooctadiene; 1,7-cyclododecadiene and vinyl cyclohexene, and thelike.

One or more reactors in series or in parallel may be used to produce themodifiers. Catalyst component and activator may be delivered as asolution or slurry, either separately to the reactor, activated in-linejust prior to the reactor or in the reactor, or preactivated and pumpedas an activated solution or slurry to the reactor. A preferred operationis two solutions activated in-line. For more information on methods tointroduce multiple catalysts into reactors, please see U.S. Pat. No.6,399,722, and PCT Publication No. WO 01/30862A1. While these referencesmay emphasize gas phase reactors, the techniques described are equallyapplicable to other types of reactors, including continuous stirred tankreactors, slurry loop reactors and the like. Polymerizations are carriedout in either single reactor operation, in which monomer, comonomers,catalyst/activator, scavenger, and optional modifiers are addedcontinuously to a single reactor or in series reactor operation, inwhich the above components are added to each of two or more reactorsconnected in series. The catalyst components can be added to the firstreactor in the series. The catalyst components may also be added to bothreactors, with one component being added to first reactor and anothercomponent to other reactors.

In one embodiment 500 ppm or less of hydrogen is added to thepolymerization, or 400 ppm or less, or 300 ppm or less. In otherembodiments at least 50 ppm of hydrogen is added to the polymerization,or 100 ppm or more, or 150 ppm or more.

In a preferred embodiment, this invention also relates to a process toproduce the branch modifier comprising contacting a catalyst, activator,ethylene, C₄ to C₄₀ alpha olefin and a polyene and obtaining aterpolymer, where the catalyst efficiency is 100,000 grams of polymerper gram of catalyst or more.

Gas phase polymerization, particularly a fluidized bed process, can beused to prepare the branched modifiers described herein. Generally, in afluidized gas bed process used for producing polymers, a gaseous streamcontaining one or more monomers is continuously cycled through afluidized bed in the presence of a catalyst under reactive conditions.The gaseous stream is withdrawn from the fluidized bed and recycled backinto the reactor.

Simultaneously, polymer product is withdrawn from the reactor and freshmonomer is added to replace the polymerized monomer. (See, for example,U.S. Pat. Nos. 4,543,399; 4,588,790; 5,028,670; 5,317,036; 5,352,749;5,405,922; 5,436,304; 5,453,471; 5,462,999; 5,616,661; and 5,668,228;all of which are fully incorporated herein by reference).

Slurry phase polymerization, particularly a slurry loop process, can beused to prepare the branched modifiers described herein. A slurrypolymerization process generally operates between 1 to about 50atmosphere pressure range (15 psi to 735 psi, 103 kPa to 5068 kPa) oreven greater and temperatures in the range of 0° C. to about 120° C. Ina slurry polymerization, a suspension of solid, particulate polymer isformed in a liquid polymerization diluent medium to which monomer andcomonomers along with catalyst are added. The suspension includingdiluent is intermittently or continuously removed from the reactor wherethe volatile components are separated from the polymer and recycled,optionally after a distillation, to the reactor. The liquid diluentemployed in the polymerization medium is typically an alkane having from3 to 7 carbon atoms, preferably a branched alkane. The medium employedshould be liquid under the conditions of polymerization and relativelyinert. When a propane medium is used the process must be operated abovethe reaction diluent critical temperature and pressure. Preferably, ahexane or an isobutane medium is employed.

In one embodiment, a preferred polymerization technique useful in theinvention is referred to as a particle form polymerization or a slurryprocess where the temperature is kept below the temperature at which thepolymer goes into solution. Such technique is well known in the art, anddescribed in, for instance, U.S. Pat. No. 3,248,179 which is fullyincorporated herein by reference. The preferred temperature in theparticle form process is within the range of about 85° C. to about 110°C. Two preferred polymerization methods for the slurry process are thoseemploying a loop reactor and those utilizing a plurality of stirredreactors in series, parallel, or combinations thereof. Non-limitingexamples of slurry processes include continuous loop or stirred tankprocesses. Also, other examples of slurry processes are described inU.S. Pat. No. 4,613,484, which is herein fully incorporated byreference.

Particle form of polymerization has advantage over solution process forproduction of branched modifier with high level of branching. Thepolymer chains produced are present in discreted granular form and thusprevent many polymer chains from cross-linking together and formingreactor gels.

In another embodiment, the slurry process is carried out continuously ina loop reactor. The catalyst, as a slurry in isobutane or as a dry freeflowing powder, is injected regularly to the reactor loop, which isitself filled with circulating slurry of growing polymer particles in adiluent of isobutane containing monomer and comonomer. Hydrogen,optionally, may be added as a molecular weight control. In oneembodiment 500 ppm or less of hydrogen is added, or 400 ppm or less or300 ppm or less. In other embodiments at least 50 ppm of hydrogen isadded, or 100 ppm or more, or 150 ppm or more.

The reactor is maintained at a pressure of 3620 kPa to 4309 kPa and at atemperature in the range of about 60° C. to about 120° C., preferably upto about 104° C. depending on the desired polymer meltingcharacteristics. Reaction heat is removed through the loop wall sincemuch of the reactor is in the form of a double-jacketed pipe. The slurryis allowed to exit the reactor at regular intervals or continuously to aheated low pressure flash vessel, rotary dryer and a nitrogen purgecolumn in sequence for removal of the diluent and all unreacted monomerand comonomers. The resulting hydrocarbon free powder is then compoundedfor use in various applications.

In yet another embodiment in the slurry process useful in the invention,the concentration of predominant monomer in the reactor liquid medium isin the range of from about 1 wt % to 30 wt %, preferably about 1 wt % to10 wt %, preferably from about 2 wt % to about 7 wt %, more preferablyfrom about 2.5 wt % to about 6 wt %, most preferably from about 3 wt %to about 6 wt %.

Another process useful in the invention is where the process, preferablya slurry process, is operated in the absence of or essentially free ofany scavengers, such as triethylaluminum, trimethylaluminum,tri-isobutylaluminum and tri-n-hexylaluminum and diethyl aluminumchloride, dibutyl zinc and the like. This process is described in PCTPublication No. WO 96/08520 and U.S. Pat. No. 5,712,352, which areherein fully incorporated by reference.

In another embodiment, the process is run with scavengers. Typicalscavengers include trimethyl aluminum, tri-isobutyl aluminum and anexcess of alumoxane or modified alumoxane.

In another embodiment, homogeneous polymerization, particularly a bulkor solution phase process, can be used to prepare the branched modifiersdescribed herein. Generally this involves polymerization in a continuousreactor in which the polymer formed and the starting monomer andcatalyst materials supplied are agitated to reduce or avoidconcentration gradients. Suitable processes operate above the meltingpoint of the polymers at high pressures, from 1 bar to 3000 bar (0.1 MPato 300 MPa), in which the monomer acts as diluent or in solutionpolymerization using a solvent.

Temperature control in the reactor is obtained by balancing the heat ofpolymerization with reactor cooling by reactor jackets or cooling coilsto cool the contents of the reactor, auto refrigeration, pre-chilledfeeds, vaporization of liquid medium (diluent, monomers or solvent) orcombinations of all three. Adiabatic reactors with pre-chilled feeds mayalso be used. The reactor temperature depends on the catalyst used. Ingeneral, the reactor temperature preferably can vary between about 30°C. and about 160° C., more preferably from about 90° C. to about 150°C., and most preferably from about 100° C. to about 140° C.Polymerization temperature may vary depending on catalyst choice. Inseries operation, the second reactor temperature is preferably higherthan the first reactor temperature. In parallel reactor operation, thetemperatures of the two reactors are independent. The pressure can varyfrom about 1 mm Hg to 2500 bar (250 MPa), preferably from 0.1 bar to1600 bar (0.1 MPa to 160 MPa), most preferably from 1.0 bar to 500 bar(0.1 MPa to 50 MPa).

In one embodiment 500 ppm or less of hydrogen is added to thepolymerization, or 400 ppm or less, or 300 ppm or less. In otherembodiments at least 50 ppm of hydrogen is added to the polymerization,or 100 ppm or more, or 150 ppm or more.

Each of these processes may also be employed in single reactor, parallelor series reactor configurations. The liquid processes comprisecontacting olefin monomers with the above described catalyst system in asuitable diluent or solvent and allowing said monomers to react for asufficient time to produce the desired polymers. Hydrocarbon solventsare suitable, both aliphatic and aromatic. Alkanes, such as hexane,pentane, isopentane, and octane, are preferred.

The process can be carried out in a continuous stirred tank reactor,batch reactor or plug flow reactor, or more than one reactor operated inseries or parallel. These reactors may have or may not have internalcooling or heating and the monomer feed may or may not be refrigerated.See the general disclosure of U.S. Pat. No. 5,001,205 for generalprocess conditions. See also, PCT Application Nos. WO 96/33227 and WO97/22639. All documents are incorporated by reference for U.S. purposesfor description of polymerization processes, metallocene selection anduseful scavenging compounds.

Preferably, the polymerization is conducted in a continuous, stirredtank reactor. Tubular reactors equipped with the hardware to introducefeeds, catalysts and scavengers in staged manner can also be used.Generally, polymerization reactors are agitated (stirred) to reduce oravoid concentration gradients. Reaction environments include the casewhere the monomer(s) acts as diluent or solvent as well as the casewhere a liquid hydrocarbon is used as diluent or solvent. Preferredhydrocarbon liquids include both aliphatic and aromatic fluids such asdesulphurized light virgin naphtha and alkanes, such as propane,isobutane, mixed butanes, hexane, pentane, isopentane, isohexane,cyclohexane, isooctane, and octane. In an alternate embodiment aperfluorocarbon or hydrofluorocarbon is used as the solvent or diluent.

Suitable conditions for polymerization include a temperature from about50° C. to about 250° C., such as from about 50° C. to about 150° C., forexample from about 70° C. to about 150° C. and a pressure of 0.1 MPa ormore, such as 2 MPa or more. The upper pressure limit is not criticallyconstrained but is typically 200 MPa or less, such as 120 MPa or less,except when operating in supercritical phase then the pressure andtemperature are above the critical point of the reaction media inquestion (typically over 95° C. and 4.6 MPa for propylenepolymerizations). For more information on running supercriticalpolymerizations, see PCT Publication No. WO 2004/026921. Temperaturecontrol in the reactor is generally obtained by balancing the heat ofpolymerization with reactor cooling via reactor jackets or coolingcoils, auto refrigeration, pre-chilled feeds, vaporization of liquidmedium (diluent, monomers or solvent) or combinations of all three.Adiabatic reactors with pre-chilled feeds may also be used.

A polymer can be recovered from the effluent of either the firstpolymerization step or the second polymerization step by separating thepolymer from other constituents of the effluent using conventionalseparation means. For example, polymer can be recovered from eithereffluent by coagulation with a non-solvent, such as methanol, isopropylalcohol, acetone, or n-butyl alcohol, or the polymer can be recovered bystripping the solvent or other media with heat or steam. One or moreconventional additives, such as antioxidants, can be incorporated in thepolymer during the recovery procedure. Possible antioxidants includephenyl-beta-naphthylamine, di-tert-butylhydroquinone, triphenylphosphate, heptylated diphenylamine,2,2′-methylene-bis(4-methyl-6-tert-butyl)phenol, and2,2,4-trimethyl-6-phenyl-1,2-dihydroquinoline. Other methods of recoverysuch as by the use of lower critical solution temperature (LCST)followed by devolatilization, are also envisioned. The catalyst may bedeactivated as part of the separation procedure to reduce or eliminatefurther uncontrolled polymerization downstream in the polymer recoveryprocesses. Deactivation may be effected by mixing with suitable polarsubstances such as water, whose residual effect following recycle can becounteracted by suitable sieves or scavenging systems.

Suitable catalysts for producing the branched modifier are those capableof polymerizing a C₂ to C₂₀ olefin to produce an ethylene copolymer.These include both metallocene and Ziegler-Natta catalysts. Thecatalysts employed in the first reaction zone should be able to producepolymers with reactive unsaturated chain ends, preferably at least 50%of vinyl unsaturation based on the total unsaturated olefin chain ends,while the catalyst used in the second reaction zone should be capable ofincorporating the polymerizable macromonomer into a growing chain toform branched block polymers. For polymerization in single reaction zoneusing mixed catalysts, at least one of the catalysts is able to producepolymers with reactive unsaturated chain ends, preferably at least 50%of vinyl unsaturation based on the total unsaturated olefin chain ends,while at least one of the catalysts is capable of incorporating thepolymerizable macromonomer into a growing chain to form branched blockpolymers. The catalysts can be in the form of a homogeneous solution,supported, or a combination thereof. In case two catalysts are employedin the same reaction zone, preferably, at least one of the catalyst isable to incorporate more comonomer (such as butene, hexene, or octene)than other catalysts so that the polymers produced will have differentdensities. A wide variety of transition metal compounds are known that,when activated with a suitable activator, will have poor alpha-olefinsincorporation and hence will produce higher density ethylene copolymers.

Metallocene catalyst compounds are generally described throughout in,for example, 1 & 2 METALLOCENE-BASED POLYOLEFINS (John Scheirs & W.Kaminsky eds., John Wiley & Sons, Ltd. 2000); G. G. Hlatky in 181COORDINATION CHEM. REV., p. 243-296 (1999) and in particular, for use inthe synthesis of polyethylene in 1 METALLOCENE-BASED POLYOLEFINS, p.261-377 (2000). The metallocene catalyst compounds as described hereininclude “half sandwich” and “full sandwich” compounds having one or moreCp ligands (cyclopentadienyl and ligands isolobal to cyclopentadienyl)bound to at least one Group 3 to Group 12 metal atom, and one or moreleaving group(s) bound to the at least one metal atom. Hereinafter,these compounds will be referred to as “metallocenes” or “metallocenecatalyst components”.

The Cp ligands are typically i-bonded and/or fused ring(s) or ringsystems. The ring(s) or ring system(s) typically comprise atoms selectedfrom the group consisting of Groups 13 to 16 atoms, and moreparticularly, the atoms that make up the Cp ligands are selected fromthe group consisting of carbon, nitrogen, oxygen, silicon, sulfur,phosphorous, germanium, boron, aluminum, and combinations thereof,wherein carbon makes up at least 50% of the ring members. Even moreparticularly, the Cp ligand(s) may be selected from the group consistingof substituted and unsubstituted cyclopentadienyl ligands and ligandsisolobal to cyclopentadienyl, non-limiting examples of which includecyclopentadienyl, indenyl, fluorenyl, and other structures. Furthernon-limiting examples of such ligands include cyclopentadienyl,cyclopentaphenanthreneyl, indenyl, benzindenyl, fluorenyl,octahydrofluorenyl, cyclooctatetraenyl, cyclopentacyclododecene,phenanthrindenyl, 3,4-benzofluorenyl, 9-phenylfluorenyl,8-H-cyclopent[a]acenaphthylenyl, 7H-dibenzofluorenyl,indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl,hydrogenated versions thereof (e.g. 4,5,6,7-tetrahydroindenyl, or“H₄Ind”), substituted versions thereof, and heterocyclic versionsthereof. In a particular embodiment, the metallocenes useful in thepresent invention may be selected from those including one or two (two,in a more particular embodiment) of the same or different Cp ringsselected from the group consisting of cyclopentadienyl, indenyl,fluorenyl, tetrahydroindenyl, and substituted versions thereof.

The metal atom “M” of the metallocene catalyst compound, as describedthroughout the specification and claims, may be selected from the groupconsisting of Groups 3 through 12 atoms and lanthanide Group atoms inone embodiment; and selected from the group consisting of Groups 3through 10 atoms in a more particular embodiment, and selected from thegroup consisting of Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co,Rh, Ir, and Ni in yet a more particular embodiment; and selected fromthe group consisting of Groups 4, 5, and 6 atoms in yet a moreparticular embodiment, and from Ti, Zr, Hf atoms in yet a moreparticular embodiment, and may be Zr in yet a more particularembodiment. The oxidation state of the metal atom “M” may range from 0to +7 in one embodiment; and in a more particular embodiment, is +1, +2,+3, +4, or +5; and in yet a more particular embodiment is +2, +3, or +4.The groups bound to the metal atom “M” are such that the compoundsdescribed below in the formulas and structures are electrically neutral,unless otherwise indicated. The Cp ligand(s) form at least one chemicalbond with the metal atom “M” to form the “metallocene catalystcompound”. The Cp ligands are distinct from the leaving groups bound tothe catalyst compound in that they are not highly susceptible tosubstitution/abstraction reactions.

In one aspect of the invention, the one or more metallocene catalystcomponents of the invention are represented by the formula (I):Cp^(A)Cp^(B)M_(X) wherein M is as described above; each X is chemicallybonded to M; each Cp group is chemically bonded to M; and n is 0, 1, 2,3, or 4, and either 1 or 2 in a particular embodiment. The ligandsrepresented by Cp^(A) and Cp^(B) in formula (I) may be the same ordifferent cyclopentadienyl ligands or ligands isolobal tocyclopentadienyl, either or both of which may contain heteroatoms andeither or both of which may be substituted by a group R. In oneembodiment, Cp^(A) and Cp^(B) are independently selected from the groupconsisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl,and substituted derivatives of each. Independently, each CpA and Cp^(B)of formula (I) may be unsubstituted or substituted with any one orcombination of substituent groups R. Non-limiting examples ofsubstituent groups R as used in formula (I) as well as ring substituentsin formulas (Va-d) include groups selected from the group consisting ofhydrogen radicals, alkyls, alkenyls, alkynyls, cycloalkyls, aryls,acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines,alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- anddialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, and combinationsthereof. More particular non-limiting examples of alkyl substituents Rassociated with formula (I) through (IVa) include methyl, ethyl, propyl,butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl,methylphenyl, tert-butylphenyl groups, and the like, including all theirisomers, for example tertiary-butyl, isopropyl, and the like. Otherpossible radicals include substituted alkyls and aryls, such as, forexample, fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl,bromohexyl, chlorobenzyl, and hydrocarbyl substituted organometalloidradicals including trimethylsilyl, trimethylgermyl, methyldiethylsilyl,and the like; halocarbyl-substituted organometalloid radicals includingtris(trifluoromethyl)silyl, methylbis(difluoromethyl)silyl,bromomethyldimethylgermyl, and the like; disubstituted boron radicalsincluding dimethylboron, for example; and disubstituted Group 15radicals including dimethylamine, dimethylphosphine, diphenylamine,methylphenylphosphine, Group 16 radicals including methoxy, ethoxy,propoxy, phenoxy, methylsulfide, and ethylsulfide. Other substituents Rinclude olefins, such as, but not limited to, olefinically-unsaturatedsubstituents including vinyl-terminated ligands, for example 3-butenyl,2-propenyl, 5-hexenyl, and the like. In one embodiment, at least two Rgroups (two adjacent R groups in one embodiment) are joined to form aring structure having from 3 to 30 atoms selected from the groupconsisting of carbon, nitrogen, oxygen, phosphorous, silicon, germanium,aluminum, boron, and combinations thereof. Also, a substituent group Rgroup, such as 1-butanyl, may form a bonding association to the elementM.

Non-limiting examples of X groups include alkyls, amines, phosphines,ethers, carboxylates, dienes, hydrocarbon radicals having from 1 to 20carbon atoms; fluorinated hydrocarbon radicals (e.g.—C₆F₅(pentafluorophenyl)), fluorinated alkylcarboxylates (e.g.CF₃C(O)O—), hydrides and halogen ions (such as chlorine or bromine) andcombinations thereof. Other examples of X ligands include alkyl groups,such as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl,tetramethylene, pentamethylene, methylidene, methoxy, ethoxy, propoxy,phenoxy, bis(N-methylanilide), dimethylamide, dimethylphosphideradicals, and the like. In one embodiment, two or more X's form a partof a fused ring or ring system.

In another aspect of the invention, the metallocene catalyst componentincludes those of formula (I) where Cp^(A) and Cp^(B) are bridged toeach other by at least one bridging group, (A), such that the structureis represented by formula (II): Cp^(A)(A)Cp^(B)MX_(n). These bridgedcompounds represented by formula (II) are known as “bridgedmetallocenes”. Cp^(A), Cp^(B), M, X, and n in formula (II) are asdefined above for formula (I); and wherein each Cp ligand is chemicallybonded to M, and (A) is chemically bonded to each Cp. Non-limitingexamples of bridging group (A) include divalent hydrocarbon groupscontaining at least one Group 13 to 16 atom, such as, but not limitedto, at least one of a carbon, oxygen, nitrogen, silicon, aluminum,boron, germanium, tin atom, and combinations thereof, wherein theheteroatom also may be C₁ to C₁₂ alkyl or aryl substituted to satisfyneutral valency. The bridging group (A) also may contain substituentgroups R as defined above (for formula (I)) including halogen radicalsand iron. More particular non-limiting examples of bridging group (A)are represented by C₁ to C₆ alkylenes, substituted C₁ to C₆ alkylenes,oxygen, sulfur, R′₂C═, R′₂Si═, —Si(R′)₂Si(R′₂)—, R′₂ Ge═, R′P═ (wherein“═” represents two chemical bonds), where R′ is independently selectedfrom the group consisting of hydride, hydrocarbyl, substitutedhydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substitutedorganometalloid, halocarbyl-substituted organometalloid, disubstitutedboron, disubstituted Group 15 atoms, substituted Group 16 atoms, andhalogen radical; and wherein two or more R′ may be joined to form a ringor ring system. In one embodiment, the bridged metallocene catalystcomponent of formula (II) has two or more bridging groups (A).

Other non-limiting examples of bridging group (A) include methylene,ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene,1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene,dimethylsilyl, diethylsilyl, methyl-ethylsilyl,trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl,di(n-propyl)silyl, di(i-propyl)silyl, di(n-hexyl)silyl,dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl,t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl, andthe corresponding moieties wherein the Si atom is replaced by a Ge or aC atom, dimethylsilyl, diethylsilyl, dimethylgermyl, and diethylgermyl.

In another embodiment, bridging group (A) also may be cyclic,comprising, for example 4 to 10 ring members (5 to 7 ring members in amore particular embodiment). The ring members may be selected from theelements mentioned above, from one or more of B, C, Si, Ge, N, and O ina particular embodiment. Non-limiting examples of ring structures whichmay be present as or part of the bridging moiety are cyclobutylidene,cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene,and the corresponding rings where one or two carbon atoms are replacedby at least one of Si, Ge, N, and O (in particular, Si and Ge). Thebonding arrangement between the ring and the Cp groups may be eithercis-, trans-, or a combination.

The cyclic bridging groups (A) may be saturated or unsaturated and/ormay carry one or more substituents and/or may be fused to one or moreother ring structures. If present, the one or more substituents areselected from the group consisting of hydrocarbyl (e.g. alkyl, such asmethyl) and halogen (e.g. F, Cl) in one embodiment. The one or more Cpgroups to which the above cyclic bridging moieties may optionally befused may be saturated or unsaturated, and may be selected from thegroup consisting of those having 4 to 10 (more particularly 5, 6, or 7)ring members (selected from the group consisting of C, N, O, and S in aparticular embodiment) such as, for example, cyclopentyl, cyclohexyl,and phenyl. Moreover, these ring structures may themselves be fused,such as, for example, in the case of a naphthyl group. Moreover, these(optionally fused) ring structures may carry one or more substituents.Illustrative, non-limiting examples of these substituents arehydrocarbyl (particularly alkyl) groups and halogen atoms.

The ligands Cp^(A) and Cp^(B) of formulae (I) and (II) are differentfrom each other in one embodiment, and the same in another embodiment.

In yet another aspect of the invention, the metallocene catalystcomponents include bridged mono-ligand metallocene compounds (e.g. monocyclopentadienyl catalyst components). In this embodiment, the at leastone metallocene catalyst component is a bridged “half-sandwich”metallocene represented by the formula (III): Cp^(A)(A)QMX_(n) whereinCp^(A) is defined above and is bound to M; (A) is a bridging groupbonded to Q and Cp^(A); and wherein an atom from the Q group is bondedto M; and n is an integer 0, 1, or 2. In formula (III) above, Cp^(A),(A), and Q may form a fused ring system. The X groups and n of formula(III) are as defined above in formula (I) and (II). In one embodiment,Cp^(A) is selected from the group consisting of cyclopentadienyl,indenyl, tetrahydroindenyl, fluorenyl, substituted versions thereof, andcombinations thereof. In formula (III), Q is a heteroatom-containingligand in which the bonding atom (the atom that is bonded with the metalM) is selected from the group consisting of Group 15 atoms and Group 16atoms in one embodiment, and selected from the group consisting ofnitrogen, phosphorus, oxygen, or sulfur atom in a more particularembodiment, and nitrogen and oxygen in yet a more particular embodiment.Non-limiting examples of Q groups include alkylamines, arylamines,mercapto compounds, ethoxy compounds, carboxylates (e.g. pivalate),carbamates, azenyl, azulene, pentalene, phosphoyl, phosphinimine,pyrrolyl, pyrozolyl, carbazolyl, borabenzene, and other compoundscomprising Group 15 and Group 16 atoms capable of bonding with M.

In yet another aspect of the invention, the at least one metallocenecatalyst component may be an unbridged “half sandwich” metallocenerepresented by the formula (IVa):

Cp ^(A) MQ _(q) X _(n)  (IVa)

wherein Cp^(A) is defined as for the Cp groups in (I) and is a ligandthat is bonded to M; each Q is independently bonded to M; X is a leavinggroup as described above in (I); n ranges from 0 to 3, and is 0 or 3 inone embodiment; q ranges from 0 to 3, and is 0 or 3 in one embodiment.

In one embodiment, Cp^(A) is selected from the group consisting ofcyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, substitutedversion thereof, and combinations thereof. In formula (IVa), Q isselected from the group consisting of ROO⁻, RO—, R(O)—, —NR—, —CR₂—,—S—, —NR₂, —CR₃, —SR, —SiR₃, —PR₂, —H, and substituted and unsubstitutedaryl groups, wherein R is selected from the group consisting of C₁ to C₆alkyls, C₆ to C₁₂ aryls, C₁ to C₆ alkylamines, C₆ to C₁₂alkylarylamines, C₁ to C₆ alkoxys, C₆ to C₁₂ aryloxys, and the like.Non-limiting examples of Q include C₁ to C₁₂ carbamates, C₁ to C₁₂carboxylates (e.g. pivalate), C₂ to C₂₀ alkyls, and C₂ to C₂₀heteroallyl moieties.

In another aspect of the invention, the metallocene catalyst componentis one or more as described in U.S. Pat. Nos. 5,703,187, and 5,747,406,including a dimer or oligomeric structure, such as disclosed in, forexample, U.S. Pat. Nos. 5,026,798 and 6,069,213. In another aspect ofthe invention, the metallocene catalyst component is one or more asdescribed in U.S. Pat. No. 6,069,213.

It is contemplated that the metallocene catalyst components describedabove include their structural or optical or enantiomeric isomers(racemic mixture), and may be a pure enantiomer in one embodiment. Asused herein, a single, bridged, asymmetrically substituted metallocenecatalyst component having a racemic and/or meso isomer does not, itself,constitute at least two different bridged, metallocene catalystcomponents. The “metallocene catalyst component” useful in the presentinvention may comprise any combination of any embodiment describedherein.

Particularly useful metallocene catalyst compounds include:dimethylsilyl-bis-(tetrahydroindenyl) zirconium dichloride,dimethylsilyl-bis-(tetrahydroindenyl) zirconium dimethyl,dimethylsilyl-bis-(tetrahydroindenyl) hafnium dichloride,dimethylsilyl-bis-(tetrahydroindenyl) hafnium dimethyl, ethylene (bisindenyl) zirconium dimethyl, ethylene (bis indenyl) zirconiumdichloride, ethylene (bis indenyl) hafnium dimethyl, ethylene (bisindenyl) hafnium dichloride, rac-dimethylsilylbis(indenyl)zirconiumdimethyl, rac-dimethylsilylbis(indenyl)zirconium dichloride,rac-dimethylsilylbis(indenyl)hafnium dimethyl, andrac-dimethylsilylbis(indenyl)hafnium dichloride.

Activators

The terms “cocatalyst” and “activator” are used herein interchangeablyand are defined to be any compound which can activate any one of thecatalyst compounds described above by converting the neutral catalystcompound to a catalytically active catalyst compound cation.Non-limiting activators, for example, include alumoxanes, aluminumalkyls, ionizing activators, which may be neutral or ionic, andconventional-type cocatalysts.

Preferred activators typically include alumoxane compounds (such asmethyl alumoxane), modified alumoxane compounds, and ionizing anionprecursor compounds that abstract a reactive, σ-bound, metal ligandmaking the metal complex cationic and providing a charge-balancingnoncoordinating or weakly coordinating anion.

In one embodiment, alumoxane activators are utilized as an activator inthe catalyst composition. Examples of useful alumoxanes includemethylalumoxane (MAO), modified methylalumoxane (MMAO), ethylalumoxaneand isobutylalumoxane. When the activator is an alumoxane (modified orunmodified), some embodiments select the maximum amount of activator ata 5000-fold molar excess Al/M over the catalyst compound (per metalcatalytic site). The minimum activator-to-catalyst-compound is a 1:1molar ratio. Alternate preferred ranges include from 1:1 to 500:1,alternately from 1:1 to 200:1, alternately from 1:1 to 100:1, oralternately from 1:1 to 50:1.

Non-coordinating anions may be used as activators herein. The term“non-coordinating anion” (NCA) means an anion which either does notcoordinate to a cation or which is only weakly coordinated to a cationthereby remaining sufficiently labile to be displaced by a neutral Lewisbase. “Compatible” non-coordinating anions are those which are notdegraded to neutrality when the initially formed complex decomposes.Further, the anion will not transfer an anionic substituent or fragmentto the cation so as to cause it to form a neutral transition metalcompound and a neutral by-product from the anion. Non-coordinatinganions useful in accordance with this invention are those that arecompatible, stabilize the transition metal cation in the sense ofbalancing its ionic charge at +1, and yet retain sufficient lability topermit displacement during polymerization.

It is within the scope of this invention to use an ionizing orstoichiometric activator, neutral or ionic, such as tri (n-butyl)ammonium tetrakis (pentafluorophenyl) borate, a tris perfluorophenylboron metalloid precursor or a tris perfluoronaphthyl boron metalloidprecursor, polyhalogenated heteroborane anions (PCT Publication No. WO98/43983), boric acid (U.S. Pat. No. 5,942,459), or combination thereof.It is also within the scope of this invention to use neutral or ionicactivators alone or in combination with alumoxane or modified alumoxaneactivators.

Examples of neutral stoichiometric activators include tri-substitutedboron, tellurium, aluminum, gallium, and indium, or mixtures thereof.The three substituent groups are each independently selected fromalkyls, alkenyls, halogens, substituted alkyls, aryls, arylhalides,alkoxy, and halides. Preferably, the three groups are independentlyselected from halogen, mono or multicyclic (including halosubstituted)aryls, alkyls, and alkenyl compounds, and mixtures thereof, preferredare alkenyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms and arylgroups having 3 to 20 carbon atoms (including substituted aryls). Morepreferably, the three groups are alkyls having 1 to 4 carbon groups,phenyl, naphthyl, or mixtures thereof. Even more preferably, the threegroups are halogenated, preferably fluorinated, aryl groups. A preferredneutral stoichiometric activator is tris perfluorophenyl boron or trisperfluoronaphthyl boron.

Ionic stoichiometric activator compounds may contain an active proton,or some other cation associated with, but not coordinated to, or onlyloosely coordinated to, the remaining ion of the ionizing compound. Suchcompounds and the like are described in European Publication Nos. EP 0570 982 A; EP 0 520 732 A; EP 0 495 375 A; EP 0 500 944 B1; EP 0 277 003A; EP 0 277 004 A; U.S. Pat. Nos. 5,153,157; 5,198,401; 5,066,741;5,206,197; 5,241,025; 5,384,299; 5,502,124; and U.S. patent applicationSer. No. 08/285,380, filed Aug. 3, 1994; all of which are herein fullyincorporated by reference.

Preferred compounds useful as an activator in the process of thisinvention comprise a cation, which is preferably a Bronsted acid capableof donating a proton, and a compatible non-coordinating anion whichanion is relatively large (bulky), capable of stabilizing the activecatalyst species (the Group 4 cation) which is formed when the twocompounds are combined and said anion will be sufficiently labile to bedisplaced by olefinic, diolefinic and acetylenically unsaturatedsubstrates or other neutral Lewis bases, such as ethers, amines, and thelike. Two classes of useful compatible non-coordinating anions have beendisclosed in European Publication Nos. EP 0 277,003 A1, and EP 0 277,004A1: 1) anionic coordination complexes comprising a plurality oflipophilic radicals covalently coordinated to and shielding a centralcharge-bearing metal or metalloid core; and 2) anions comprising aplurality of boron atoms such as carboranes, metallacarboranes, andboranes.

In a preferred embodiment, the stoichiometric activators include acation and an anion component, and are preferably represented by thefollowing formula (II):

(Z)_(d) ⁺(A ^(d−))  (II)

wherein Z is (L-H) or a reducible Lewis Acid, L is an neutral Lewisbase; H is hydrogen; (L-H)⁺ is a Bronsted acid; A^(d−) is anon-coordinating anion having the charge d−; and d is an integer from 1to 3.

When Z is (L-H) such that the cation component is (L-H)_(d) ⁺, thecation component may include Bronsted acids such as protonated Lewisbases capable of protonating a moiety, such as an alkyl or aryl, fromthe bulky ligand metallocene containing transition metal catalystprecursor, resulting in a cationic transition metal species. Preferably,the activating cation (L-H)_(d) ⁺ is a Bronsted acid, capable ofdonating a proton to the transition metal catalytic precursor resultingin a transition metal cation, including ammoniums, oxoniums,phosphoniums, silyliums, and mixtures thereof, preferably ammoniums ofmethylamine, aniline, dimethylamine, diethylamine, N-methylaniline,diphenylamine, trimethylamine, triethylamine, N,N-dimethylaniline,methyldiphenylamine, pyridine, p-bromo N,N-dimethylaniline,p-nitro-N,N-dimethylaniline, phosphoniums from triethylphosphine,triphenylphosphine, and diphenylphosphine, oxoniums from ethers, such asdimethyl ether diethyl ether, tetrahydrofuran, and dioxane, sulfoniumsfrom thioethers, such as diethyl thioethers and tetrahydrothiophene, andmixtures thereof.

When Z is a reducible Lewis acid it is preferably represented by theformula: (Ar₃C⁺), where Ar is aryl or aryl substituted with aheteroatom, a C₁ to C₄₀ hydrocarbyl, or a substituted C₁ to C₄₀hydrocarbyl, preferably the reducible Lewis acid is represented by theformula: (Ph₃C⁺), where Ph is phenyl or phenyl substituted with aheteroatom, a C₁ to C₄₀ hydrocarbyl, or a substituted C₁ to C₄₀hydrocarbyl. In a preferred embodiment, the reducible Lewis acid istriphenyl carbenium.

The anion component A^(d−) includes those having the formula[M^(k+)Q_(n)]d⁻ wherein k is 1, 2, or 3; n is 1, 2, 3, 4, 5, or 6,preferably 3, 4, 5 or 6; n−k=d; M is an element selected from Group 13of the Periodic Table of the Elements, preferably boron or aluminum, andQ is independently a hydride, bridged or unbridged dialkylamido, halide,alkoxide, aryloxide, hydrocarbyl, substituted hydrocarbyl, halocarbyl,substituted halocarbyl, and halosubstituted-hydrocarbyl radicals, said Qhaving up to 20 carbon atoms with the proviso that in not more than oneoccurrence is Q a halide, and two Q groups may form a ring structure.Preferably, each Q is a fluorinated hydrocarbyl group having 1 to 20carbon atoms, more preferably each Q is a fluorinated aryl group, andmost preferably each Q is a pentafluoryl aryl group. Examples ofsuitable A^(d−) components also include diboron compounds as disclosedin U.S. Pat. No. 5,447,895, which is fully incorporated herein byreference.

In another embodiment, the NCA is a Bulky activator. A “Bulky activator”as used herein refers to anionic activators represented by the formula:

where:each R₁ is, independently, a halide, preferably a fluoride;each R₂ is, independently, a halide, a C₆ to C₂₀ substituted aromatichydrocarbyl group or a siloxy group of the formula —O—Si—Ra, where R_(a)is a C₁ to C₂₀ hydrocarbyl or hydrocarbylsilyl group (preferably R₂ is afluoride or a perfluorinated phenyl group); each R₃ is a halide, C₆ toC₂₀ substituted aromatic hydrocarbyl group or a siloxy group of theformula —O—Si—Ra, where R_(a) is a C₁ to C₂₀ hydrocarbyl orhydrocarbylsilyl group (preferably R₃ is a fluoride or a C₆perfluorinated aromatic hydrocarbyl group); wherein R₂ and R₃ can formone or more saturated or unsaturated, substituted or unsubstituted rings(preferably R₂ and R₃ form a perfluorinated phenyl ring);L is an neutral Lewis base; (L-H)⁺ is a Bronsted acid; d is 1, 2, or 3;wherein the anion has a molecular weight of greater than 1020 g/mol; andwherein at least three of the substituents on the B atom each have amolecular volume of greater than 250 cubic Å, alternately greater than300 cubic Å, or alternately greater than 500 cubic Å.

“Molecular volume” is used herein as an approximation of spatial stericbulk of an activator molecule in solution. Comparison of substituentswith differing molecular volumes allows the substituent with the smallermolecular volume to be considered “less bulky” in comparison to thesubstituent with the larger molecular volume. Conversely, a substituentwith a larger molecular volume may be considered “more bulky” than asubstituent with a smaller molecular volume.

Molecular volume may be calculated as reported in “A Simple ‘Back of theEnvelope’ Method for Estimating the Densities and Molecular Volumes ofLiquids and Solids,” Journal of Chemical Education, Vol. 71, No. 11,November 1994, p. 962-964. Molecular volume (MV), in units of cubic A,is calculated using the formula: MV=8.3V_(s), where V_(s) is the scaledvolume. V_(s) is the sum of the relative volumes of the constituentatoms, and is calculated from the molecular formula of the substituentusing the following table of relative volumes. For fused rings, theV_(s) is decreased by 7.5% per fused ring.

Element Relative Volume H 1 1^(st) short period, Li to F 2 2^(nd) shortperiod, Na to Cl 4 1^(st) long period, K to Br 5 2^(nd) long period, Rbto I 7.5 3^(rd) long period, Cs to Bi 9Exemplary activators useful herein include: methylalumoxane, modifiedmethylalumoxane,N,N-dimethylanilinium tetrakis(heptafluoronaphthyl)borate,N,N-dimethylanilinium tetrakis(perfluorophenyl)borate,N,N-dimethylanilinium tetrakis(perfluorobiphenyl)borate,N,N-dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate,triphenylcarbenium tetrakis(perfluoronaphthyl)borate,triphenylcarbenium tetrakis(perfluorobiphenyl)borate,triphenylcarbenium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, andtriphenylcarbenium tetra(perfluorophenyl)borate.

Further, the typical NCA activator-to-catalyst ratio, e.g. all NCAactivators-to-catalyst ratio is a 1:1 molar ratio. Alternate preferredranges include from 0.1:1 to 100:1, alternately from 0.5:1 to 200:1,alternately from 1:1 to 500:1 alternately from 1:1 to 1000:1. Aparticularly useful range is from 0.5:1 to 10:1, preferably 1:1 to 5:1.

It is also within the scope of this invention that the catalystcompounds can be combined with combinations of alumoxanes and NCA's (seefor example, U.S. Pat. Nos. 5,153,157; 5,453,410; European PublicationNo. EP 0 573 120 B1; PCT Publication Nos. WO 94/07928; and WO 95/14044;which discuss the use of an alumoxane in combination with an ionizingactivator).

Optional Support Materials

In embodiments herein, the catalyst system may comprise an inert supportmaterial. Preferably the supported material is a porous supportmaterial, for example, talc, and inorganic oxides. Other supportmaterials include zeolites, clays, organoclays, or any other organic orinorganic support material and the like, or mixtures thereof.

Preferably, the support material is an inorganic oxide in a finelydivided form. Suitable inorganic oxide materials for use in metallocenecatalyst systems herein include Groups 2, 4, 13, and 14 metal oxides,such as silica, alumina, and mixtures thereof. Other inorganic oxidesthat may be employed either alone or in combination with the silica, oralumina are magnesia, titania, zirconia, and the like. Other suitablesupport materials, however, can be employed, for example, finely dividedfunctionalized polyolefins, such as finely divided polyethylene.Particularly useful supports include magnesia, titania, zirconia,montmorillonite, phyllosilicate, zeolites, talc, clays, and the like.Also, combinations of these support materials may be used, for example,silica-chromium, silica-alumina, silica-titania, and the like. Preferredsupport materials include Al₂O₃, ZrO₂, SiO₂, and combinations thereof,more preferably SiO₂, Al₂O₃, or SiO₂/Al₂O₃.

It is preferred that the support material, most preferably an inorganicoxide, has a surface area in the range of from about 10 to about 700m²/g, pore volume in the range of from about 0.1 to about 4.0 cc/g andaverage particle size in the range of from about 5 to about 500 m. Morepreferably, the surface area of the support material is in the range offrom about 50 to about 500 m²/g, pore volume of from about 0.5 to about3.5 cc/g and average particle size of from about 10 to about 200 m. Mostpreferably the surface area of the support material is in the range offrom about 100 to about 400 m²/g, pore volume from about 0.8 to about3.0 cc/g and average particle size is from about 5 to about 100 m. Theaverage pore size of the support material useful in the invention is inthe range of from 10 to 1000 Å, preferably 50 to about 500 A, and mostpreferably 75 to about 350 Å. In some embodiments, the support materialis a high surface area, amorphous silica (surface area=300 m²/gm; porevolume of 1.65 cm³/gm). Preferred silicas are marketed under thetradenames of DAVISON 952 or DAVISON 955 by the Davison ChemicalDivision of W. R. Grace and Company. In other embodiments DAVISON 948 isused.

Ethylene Polymers

The modifiers described herein are blended with at least one ethylenepolymer to prepare the compositions of this invention.

In one aspect of the invention, the ethylene polymer is selected fromethylene homopolymers, ethylene copolymers, and blends thereof. Usefulcopolymers comprise one or more comonomers in addition to ethylene andcan be a random copolymer, a statistical copolymer, a block copolymer,and/or blends thereof. In particular, the ethylene polymer blendsdescribed herein may be physical blends or in situ blends of more thanone type of ethylene polymer or blends of ethylene polymers withpolymers other than ethylene polymers where the ethylene polymercomponent is the majority component (e.g. greater than 50 wt %).

The method of making the polyethylene is not critical, as it can be madeby slurry, solution, gas phase, high pressure or other suitableprocesses, and by using catalyst systems appropriate for thepolymerization of polyethylenes, such as Ziegler-Natta-type catalysts,chromium catalysts, metallocene-type catalysts, other appropriatecatalyst systems or combinations thereof, or by free-radicalpolymerization. In a preferred embodiment, the ethylene polymers aremade by the catalysts, activators and processes described in U.S. Pat.Nos. 6,342,566; 6,384,142; 5,741,563; PCT Publication Nos. WO 03/040201;and WO 97/19991. Such catalysts are well known in the art, and aredescribed in, for example, ZIEGLER CATALYSTS (Gerhard Fink, RolfMulhaupt and Hans H. Brintzinger, eds., Springer-Verlag 1995); Resconiet al.; and I, II METALLOCENE-BASED POLYOLEFINS (Wiley & Sons 2000).

Preferred ethylene polymers and copolymers that are useful in thisinvention include those sold by ExxonMobil Chemical Company in HoustonTex., including those sold as ExxonMobil HDPE, ExxonMobil LLDPE, andExxonMobil LDPE; and those sold under the ENABLE™, EXACT™, EXCEED™,ESCORENE™, EXXCO™, ESCOR™, PAXON™, and OPTEMA™ tradenames.

Preferred ethylene homopolymers and copolymers useful in this inventiontypically have:

-   1. an Mw of 20,000 g/mol or more, 20,000 to 2,000,000 g/mol    preferably 30,000 to 1,000,000, preferably 40,000 to 200,000,    preferably 50,000 to 750,000, as measured by size exclusion    chromatography according to the procedure described in the Test    Methods section below; and/or-   2. an Mw/M_(n) of 1 to 40, preferably 1.6 to 20, more preferably 1.8    to 10, more preferably 1.8 to 4, preferably 8 to 25 as measured by    size exclusion chromatography as described in the Test Methods    section below; and/or-   3. a T_(m) of 30° C. to 150° C., preferably 30° C. to 140° C.,    preferably 50° C. to 140° C., more preferably 60° C. to 135° C. as    determined by the DSC method described in the Test Methods section    below; and/or-   4. a crystallinity of 5% to 80%, preferably 10% to 70%, more    preferably 20% to 60% (alternatively, the polyethylene may have a    crystallinity of at least 30%, preferably at least 40%,    alternatively at least 50%, where crystallinity is determined by the    DSC method described in the Test Methods section below); and/or-   5. a heat of fusion of 300 J/g or less, preferably 1 to 260 J/g,    preferably 5 to 240 J/g, preferably 10 to 200 J/g as measured by the    DSC method described in the Test Methods section below; and/or-   6. a crystallization temperature (Tc) of 15° C. to 130° C.,    preferably 20° C. to 120° C., more preferably 25° C. to 110° C.,    preferably 60° C. to 125° C., as measured by the method described in    the Test Methods section below; and/or-   7. a heat deflection temperature of 30° C. to 120° C., preferably    40° C. to 100° C., more preferably 50° C. to 80° C. as measured    according to ASTM D648 on injection molded flexure bars, at 66 psi    load (455 kPa); and/or-   8. a Shore hardness (D scale) of 10 or more, preferably 20 or more,    preferably 30 or more, preferably 40 or more, preferably 100 or    less, preferably from 25 to 75 (as measured by ASTM D 2240); and/or-   9. a percent amorphous content of at least 50%, alternatively at    least 60%, alternatively at least 70%, even alternatively between    50% and 95%, or 70% or less, preferably 60% or less, preferably 50%    or less as determined by subtracting the percent crystallinity from    100; and/or-   10. a branching index (g′_(vis)) of 0.97 or more, preferably 0.98 or    more, preferably 0.99 or more, preferably 1, as measured using the    method described in the Test Methods section below, and/or-   11. a density of 0.860 to 0.980 g/cc (preferably from 0.880 to 0.940    g/cc, preferably from 0.900 to 0.935 g/cc, preferably from 0.910 to    0.930 g/cc) (alternately from 0.85 to 0.97 g/cm³, preferably 0.86 to    0.965 g/cm³, preferably 0.88 to 0.96 g/cm³, alternatively between    0.860 and 0.910 g/cm³, alternatively between 0.910 and 0.940 g/cm³,    or alternatively between 0.94 to 0.965 g/cm³) (determined according    to ASTM D 1505 using a density-gradient column on a    compression-molded specimen that has been slowly cooled to room    temperature (i.e. over a period of 10 minutes or more) and allowed    to age for a sufficient time that the density is constant within    +/−0.001 g/cm³).

The polyethylene may be an ethylene homopolymer, such as HDPE. Inanother embodiment the ethylene homopolymer has a molecular weightdistribution (Mw/Mn) of up to 40, preferably ranging from 1.5 to 20, andfrom 1.8 to 10 in another embodiment, and from 1.9 to 5 in yet anotherembodiment, and from 2.0 to 4 in yet another embodiment. In anotherembodiment, the 1% secant flexural modulus (determined according to ASTMD790A, where test specimen geometry is as specified under the ASTM D790section “Molding Materials (Thermoplastics and Thermosets),” and thesupport span is 2 inches (5.08 cm)) of the ethylene polymer falls in arange of 200 to 1000 MPa, and from 300 to 800 MPa in another embodiment,and from 400 to 750 MPa in yet another embodiment, wherein a desirablepolymer may exhibit any combination of any upper flexural modulus limitwith any lower flexural modulus limit. The melt index (MI) of preferredethylene homopolymers range from 0.05 to 800 dg/min in one embodiment,and from 0.1 to 100 dg/min in another embodiment, as measured accordingto ASTM D1238 (190° C., 2.16 kg).

In a preferred embodiment, the polyethylene comprises less than 20 mol %propylene units (preferably less than 15 mol %, preferably less than 10mol %, preferably less than 5 mol %, preferably 0 mol % propyleneunits).

In another embodiment of the invention, the ethylene polymer usefulherein is produced by polymerization of ethylene and, optionally, analpha-olefin with a catalyst having as a transition metal component abis(n-C₃₋₄alkyl cyclopentadienyl) hafnium compound, wherein thetransition metal component preferably comprises from about 95 mol % toabout 99 mol % of the hafnium compound as further described in U.S. Pat.No. 9,956,088.

In another embodiment of the invention, the ethylene polymer is anethylene copolymer, either random, or block, of ethylene and one or morecomonomers selected from C₃ to C₂₀ α-olefins, typically from C₃ to C₁₀α-olefins in another embodiment. Preferably, the comonomers are presentfrom 0.1 wt % to 50 wt % of the copolymer in one embodiment, and from0.5 wt % to 30 wt % in another embodiment, and from 1 wt % to 15 wt % inyet another embodiment, and from 0.1 wt % to 5 wt % in yet anotherembodiment, wherein a desirable copolymer comprises ethylene and C₃ toC₂₀ α-olefin derived units in any combination of any upper wt % limitwith any lower wt % limit described herein. Preferably the ethylenecopolymer will have a weight average molecular weight of from greaterthan 8,000 g/mol in one embodiment, and greater than 10,000 g/mol inanother embodiment, and greater than 12,000 g/mol in yet anotherembodiment, and greater than 20,000 g/mol in yet another embodiment, andless than 1,000,000 g/mol in yet another embodiment, and less than800,000 g/mol in yet another embodiment, wherein a desirable copolymermay comprise any upper molecular weight limit with any lower molecularweight limit described herein.

In another embodiment, the ethylene copolymer comprises ethylene and oneor more other monomers selected from the group consisting of C₃ to C₂₀linear, branched or cyclic monomers, and in some embodiments is a C₃ toC₁₂ linear or branched alpha-olefin, preferably butene, pentene, hexene,heptene, octene, nonene, decene, dodecene, 4-methyl-pentene-1, 3-methylpentene-1, 3,5,5-trimethyl-hexene-1, and the like. The monomers may bepresent at up to 50 wt %, preferably from 0 wt % to 40 wt %, morepreferably from 0.5 wt % to 30 wt %, more preferably from 2 wt % to 30wt %, more preferably from 5 wt % to 20 wt %.

Preferred linear alpha-olefins useful as comonomers for the ethylenecopolymers useful in this invention include C₃ to C₈ alpha-olefins, morepreferably 1-butene, 1-hexene, and 1-octene, even more preferably1-hexene. Preferred branched alpha-olefins include 4-methyl-1-pentene,3-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene, 5-ethyl-1-nonene.Preferred aromatic-group-containing monomers contain up to 30 carbonatoms. Suitable aromatic-group-containing monomers comprise at least onearomatic structure, preferably from one to three, more preferably aphenyl, indenyl, fluorenyl, or naphthyl moiety. Thearomatic-group-containing monomer further comprises at least onepolymerizable double bond such that after polymerization, the aromaticstructure will be pendant from the polymer backbone. The aromatic-groupcontaining monomer may further be substituted with one or morehydrocarbyl groups including but not limited to C₁ to C₁₀ alkyl groups.Additionally, two adjacent substitutions may be joined to form a ringstructure. Preferred aromatic-group-containing monomers contain at leastone aromatic structure appended to a polymerizable olefinic moiety.Particularly, preferred aromatic monomers include styrene,alpha-methylstyrene, para-alkylstyrenes, vinyltoluenes,vinylnaphthalene, allyl benzene, and indene, especially styrene,paramethyl styrene, 4-phenyl-1-butene and allyl benzene.

Preferred diolefin monomers useful in this invention include anyhydrocarbon structure, preferably C₄ to C₃₀, having at least twounsaturated bonds, wherein at least two of the unsaturated bonds arereadily incorporated into a polymer by either a stereospecific or anon-stereospecific catalyst(s). It is further preferred that thediolefin monomers be selected from alpha, omega-diene monomers (i.e.di-vinyl monomers). More preferably, the diolefin monomers are lineardi-vinyl monomers, most preferably those containing from 4 to 30 carbonatoms. Examples of preferred dienes include butadiene, pentadiene,hexadiene, heptadiene, octadiene, nonadiene, decadiene, undecadiene,dodecadiene, tridecadiene, tetradecadiene, pentadecadiene,hexadecadiene, heptadecadiene, octadecadiene, nonadecadiene, icosadiene,heneicosadiene, docosadiene, tricosadiene, tetracosadiene,pentacosadiene, hexacosadiene, heptacosadiene, octacosadiene,nonacosadiene, triacontadiene, particularly preferred dienes include1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene,1,13-tetradecadiene, and low molecular weight polybutadienes (M_(w) lessthan 1000 g/mol). Preferred cyclic dienes include cyclopentadiene,vinylnorbomene, norbomadiene, ethylidene norbomene, divinylbenzene,dicyclopentadiene or higher ring containing diolefins with or withoutsubstituents at various ring positions.

In a preferred embodiment, one or more dienes are present in theethylene polymer at up to 10 wt %, preferably at 0.00001 wt % to 2 wt %,preferably 0.002 wt % to 1 wt %, even more preferably 0.003 wt % to 0.5wt %, based upon the total weight of the composition. In someembodiments 500 ppm or less of diene is added to the polymerization,preferably 400 ppm or less, preferably or 300 ppm or less. In otherembodiments at least 50 ppm of diene is added to the polymerization, or100 ppm or more, or 150 ppm or more.

In a particularly desirable embodiment, the ethylene polymer used hereinis a plastomer having a density of 0.91 g/cm³ or less, as determined byASTM D1505, and a melt index (MI) between 0.1 and 50 dg/min, asdetermined by ASTM D1238 (190° C., 2.16 kg). In one embodiment, theuseful plastomer is a copolymer of ethylene and at least one C₃ to C₁₂α-olefin, preferably C₄ to C₈ α-olefins. The amount of C₃ to C₁₂α-olefin present in the plastomer ranges from 2 wt % to 35 wt % in oneembodiment, and from 5 wt % to 30 wt % in another embodiment, and from15 wt % to 25 wt % in yet another embodiment, and from 20 wt % to 30 wt% in yet another embodiment.

Preferred plastomers useful in the invention have a melt index ofbetween 0.1 and 40 dg/min in one embodiment, and from 0.2 to 20 dg/minin another embodiment, and from 0.5 to 10 dg/min in yet anotherembodiment. The average molecular weight of preferred plastomers rangesfrom 10,000 to 800,000 g/mole in one embodiment, and from 20,000 to700,000 g/mole in another embodiment. The 1% secant flexural modulus(ASTM D790A Flexural properties at room temperature are determinedaccording to ASTM D790A,-test specimen geometry was as specified underthe ASTM D790 section “Molding Materials (Thermoplastics andThermosets),” and the support span was 2 inches (5.08 cm).) of preferredplastomers ranges from 5 MPa to 100 MPa in one embodiment, and from 10MPa to 50 MPa in another embodiment. Further, preferred plastomers thatare useful in compositions of the present invention have a meltingtemperature (Tm) of from 30° C. to 100° C. in one embodiment, and from40° C. to 80° C. in another embodiment. The degree of crystallinity ofpreferred plastomers is between 3% and 30%.

Particularly, preferred plastomers useful in the present invention aresynthesized using a single-site catalyst, such as a metallocenecatalyst, and comprise copolymers of ethylene and higher α-olefins suchas propylene, 1-butene, 1-hexene and 1-octene, and which contain enoughof one or more of these comonomer units to yield a density between 0.86and 0.91 g/cm³ in one embodiment. The molecular weight distribution(Mw/Mn) of desirable plastomers ranges from 1.5 to 5 in one embodimentand from 2.0 to 4 in another embodiment.

Examples of commercially available plastomers are EXACT™ 4150, acopolymer of ethylene and 1-hexene, the 1-hexene derived units making upfrom 18 wt % to 22 wt % of the plastomer and having a density of 0.895g/cm³ and MI of 3.5 dg/min (ExxonMobil Chemical Company, Houston, Tex.);and EXACT™ 8201, a copolymer of ethylene and 1-octene, the 1-octenederived units making up from 26 wt % to 30 wt % of the plastomer, andhaving a density of 0.882 g/cm³ and MI of 1.0 dg/min (ExxonMobilChemical Company, Houston, Tex.).

The melt index (MI) of preferred ethylene polymers, as measuredaccording to ASTM D1238 (190° C., 2.16 kg), ranges from 0.02 dg/min to800 dg/min in one embodiment, from 0.05 to 500 dg/min in anotherembodiment, and from 0.1 to 100 dg/min in another embodiment. In anotherembodiment of the present invention, the polyethylene has a MI of 20dg/min or less, 7 dg/min or less, 5 dg/min or less, or 2 dg/min or less,or less than 2 dg/min. In yet another embodiment, the polymer has aMooney viscosity, ML(1+4) @125° C. (measured according to ASTM D1646) of100 or less, 75 or less, 60 or less, or 30 or less.

In yet another embodiment, the 1% secant flexural modulus of preferredethylene polymers ranges from 5 MPa to 1000 MPa, and from 10 MPa to 800MPa in another embodiment, and from 5 MPa to 200 MPa in yet anotherembodiment, wherein a desirable polymer may exhibit any combination ofany upper flexural modulus limit with any lower flexural modulus limit.

The crystallinity of the polymer may also be expressed in terms ofcrystallinity percent. The thermal energy for the highest order ofpolyethylene is estimated at 290 J/g. That is, 100% crystallinity isequal to 290 J/g. Preferably, the polymer has a crystallinity (asdetermined by DSC as described in the Test Methods section below) withinthe range having an upper limit of 80%, 60%, 40%, 30%, or 20%, and alower limit of 1%, 3%, 5%, 8%, or 10%. Alternately, the polymer has acrystallinity of 5% to 80%, preferably 10% to 70, more preferably 20% to60%. Alternatively the polyethylene may have a crystallinity of at least30%, preferably at least 40%, alternatively at least 50%, wherecrystallinity is determined.

The level of crystallinity may be reflected in the melting point. In oneembodiment of the present invention, the ethylene polymer has a singlemelting point. Typically, a sample of ethylene copolymer will showsecondary melting peaks adjacent to the principal peak, which isconsidered together as a single melting point. The highest of thesepeaks is considered the melting point. The polymer preferably has amelting point (as determined by DSC as described in the Test Methodssection below) ranging from an upper limit of 150° C., 130° C. or 100°C. to a lower limit of 0° C., 30° C., 35° C., 40° C., or 45° C.

Preferred ethylene copolymers useful herein are preferably a copolymercomprising at least 50 wt % ethylene and having up to 50 wt %,preferably 1 wt % to 35 wt %, even more preferably 1 wt % to 6 wt % of aC₃ to C₂₀ comonomer (preferably hexene or octene), based upon the weightof the copolymer. The polyethylene copolymers preferably have acomposition distribution breadth index (CDBI) of 60% or more, preferably60% to 80%, preferably 65% to 80%. In another preferred embodiment, theethylene copolymer has a density of 0.910 to 0.950 g/cm³ (preferably0.915 to 0.940 g/cm³, preferably 0.918 to 0.925 g/cm³) and a CDBI of 60%to 80%, preferably between 65% and 80%. Preferably these polymers aremetallocene polyethylenes (mPEs).

Further useful mPEs include those described in U.S. Publication No.2007/0260016 and U.S. Pat. No. 6,476,171, e.g. copolymers of an ethyleneand at least one alpha olefin having at least 5 carbon atoms obtainableby a continuous gas phase polymerization using supported catalyst of anactivated molecularly discrete catalyst in the substantial absence of analuminum alkyl based scavenger (e.g. triethylaluminum,trimethylaluminum, tri-isobutyl aluminum, tri-n-hexylaluminum and thelike), which polymer has a Melt Index of from 0.1 to 15 (ASTM D 1238,condition E); a CDBI of at least 70%, a density of from 0.910 to 0.930g/cc; a Haze (ASTM D1003) value of less than 20; a Melt Index ratio(I21/I11, ASTMD 1238) of from 35 to 80; an averaged Modulus (M) (asdefined in U.S. Pat. No. 6,255,426) of from 20,000 to 60,000 psi (13790to 41369 N/cm²) and a relation between M and the Dart Impact Strength(26 inch, ASTM D 1709) in g/mil (DIS) complying with the formula:

DIS≧0.8×[100+e ^((11.71-0.000268×M+2.183×10) ⁻⁹ ^(×M) ² ⁾],

where “e” represents 2.1783, the base Napierian logarithm, M is theaveraged Modulus in psi and DIS is the 26 inch (66 cm) dart impactstrength.

Useful mPE homopolymers or copolymers may be produced using mono- orbis-cyclopentadienyl transition metal catalysts in combination with anactivator of alumoxane and/or a non-coordinating anion in solution,slurry, high pressure or gas phase. The catalyst and activator may besupported or unsupported and the cyclopentadienyl rings may besubstituted or unsubstituted. Several commercial products produced withsuch catalyst/activator combinations are commercially available fromExxonMobil Chemical Company in Baytown, Tex. under the tradename EXCEED™Polyethylene or ENABLE™ Polyethylene.

Additives

The polyethylene compositions of the present invention may also containother additives. Those additives include antioxidants, nucleatingagents, acid scavengers, stabilizers, anticorrosion agents,plasticizers, blowing agents, cavitating agents, surfactants, adjuvants,block, antiblock, UV absorbers such as chain-breaking antioxidants,etc., quenchers, antistatic agents, slip agents, processing aids, UVstabilizers, neutralizers, lubricants, waxes, color masterbatches,pigments, dyes and fillers and cure agents such as peroxide. In apreferred embodiment, the additives may each individually present at0.01 wt % to 50 wt % in one embodiment, from 0.01 wt % to 10 wt % inanother embodiment, and from 0.1 wt % to 6 wt % in another embodiment,based upon the weight of the composition.

In a preferred embodiment, dyes and other colorants common in theindustry may be present from 0.01 wt % to 10 wt % in one embodiment, andfrom 0.1 wt % to 6 wt % in another embodiment, based upon the weight ofthe composition. Preferred fillers, cavitating agents and/or nucleatingagents include titanium dioxide, calcium carbonate, barium sulfate,silica, silicon dioxide, carbon black, sand, glass beads, mineralaggregates, talc, clay and the like.

In particular, antioxidants and stabilizers such as organic phosphites,hindered amines, and phenolic antioxidants may be present in thepolyethylene compositions of the invention from 0.001 wt % to 2 wt %,based upon the weight of the composition, in one embodiment, and from0.01 wt % to 0.8 wt % in another embodiment, and from 0.02 wt % to 0.5wt % in yet another embodiment. Non-limiting examples of organicphosphites that are suitable are tris(2,4-di-tert-butylphenyl)phosphite(IRGAFOS 168) and di(2,4-di-tert-butylphenyl)pentaerithritol diphosphite(ULTRANOX 626). Non-limiting examples of hindered amines include poly[2-N,N′-di(2,2,6,6-tetramethyl-4-piperidinyl)-hexanediamine-4-(1-amino-1,1,3,3-tetramethylbutane)sym-triazine](CHIMASORB944); bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate (TINUVIN 770).Non-limiting examples of phenolic antioxidants include pentaerythrityltetrakis(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (IRGANOX 1010);and 1,3,5-Tri(3,5-di-tert-butyl-4-hydroxybenzyl-isocyanurate (IRGANOX3114).

Fillers may be present from 0.001 wt % to 50 wt % in one embodiment, andfrom 0.01 wt % to 25 wt %, based upon the weight of the composition, inanother embodiment, and from 0.2 wt % to 10 wt % in yet anotherembodiment. Desirable fillers include but are not limited to titaniumdioxide, silicon carbide, silica (and other oxides of silica,precipitated or not), antimony oxide, lead carbonate, zinc white,lithopone, zircon, corundum, spinel, apatite, Barytes powder, bariumsulfate, magnesiter, carbon black, dolomite, calcium carbonate, talc andhydrotalcite compounds of the ions Mg, Ca, or Zn with Al, Cr or Fe andCO₃ and/or HPO₄, hydrated or not; quartz powder, hydrochloric magnesiumcarbonate, glass fibers, clays, alumina, and other metal oxides andcarbonates, metal hydroxides, chrome, phosphorous and brominated flameretardants, antimony trioxide, silica, silicone, and blends thereof.These fillers may particularly include any other fillers and porousfillers and supports known in the art, and may have the modifier of theinvention pre-contacted, or pre-absorbed into the filler prior toaddition to the ethylene polymer in one embodiment.

Metal salts of fatty acids may also be present in the polyethylenecompositions of the present invention. Such salts may be present from0.001 wt % to 1 wt % of the composition in one embodiment, and from 0.01wt % to 0.8 wt % in another embodiment. Examples of fatty acids includelauric acid, stearic acid, succinic acid, stearyl lactic acid, lacticacid, phthalic acid, benzoic acid, hydroxystearic acid, ricinoleic acid,naphthenic acid, oleic acid, palmitic acid, erucic acid, or anymonocarboxylic aliphatic saturated or unsaturated acid having a chainlength of 7 to 22 carbon atoms. Suitable metals include Li, Na, Mg, Ca,Sr, Ba, Zn, Cd, Al, Sn, Pb, and so forth. Preferably, metal salts offatty acids are magnesium stearate, calcium stearate, sodium stearate,zinc stearate, calcium oleate, zinc oleate, and magnesium oleate.

In a preferred embodiment, slip additives may be present in thecompositions of this invention. Preferably, the slip additives arepresent at 0.001 wt % to 1 wt % (10 ppm to 10,000 ppm), more preferably0.01 wt % to 0.5 wt % (100 ppm to 5000 ppm), more preferably 0.1 wt % to0.3 wt % (1000 ppm to 3000 ppm), based upon the weight of thecomposition. Desirable slip additives include but are not limited tosaturated fatty acid amides (such as palmitamide, stearamide,arachidamide, behenamide, stearyl stearamide, palmityl pamitamide, andstearyl arachidamide); saturated ethylene-bis-amides (such asstearamido-ethyl-stearamide, stearamido-ethyl-palmitamide, andpalmitamido-ethyl-stearamide); unsaturated fatty acid amides (such asoleamide, erucamide, and linoleamide); unsaturated ethylene-bis-amides(such as ethylene-bis-stearamide, ethylene-bis-oleamide,stearyl-erucamide, erucamido-ethyl-erucamide, oleamido-ethyl-oleamide,erucamido-ethyl-oleamide, oleamido-ethy-lerucamide,stearamido-ethyl-erucamide, erucamido-ethyl-palmitamide, andpalmitamido-ethyl-oleamide); glycols; polyether polyols (such asCarbowax); acids of aliphatic hydrocarbons (such as adipic acid andsebacic acid); esters of aromatic or aliphatic hydrocarbons (such asglycerol monostearate and pentaerythritol monooleate);styrene-alpha-methyl styrene; fluoro-containing polymers (such aspolytetrafluoroethylene, fluorine oils, and fluorine waxes); siliconcompounds (such as silanes and silicone polymers, including siliconeoils, modified silicones and cured silicones); sodium alkylsulfates,alkyl phosphoric acid esters; and mixtures thereof. Preferred slipadditives are unsaturated fatty acid amides, which are commerciallyavailable from Crompton (Kekamide™ grades), Croda Universal (Crodamide™grades), and Akzo Nobel Amides Co. Ltd. (ARMOSLIP™ grades).

Particularly, preferred slip agents include unsaturated fatty acidamides having the chemical structure:

CH₃(CH₂)₇CH═CH(CH₂)_(x)CONH₂

where x is 5 to 15. Preferred versions include: 1) Erucamide, where x is11, also referred to as cis-13-docosenoamide (commercially available asARMOSLIP E); 2) Oleylamide, where x is 8; and 3) Oleamide, where x is 7,also referred to as N-9-octadecenyl-hexadecanamide. In anotherembodiment, stearamide is also useful in this invention. Other preferredslip additives include those described in PCT Publication No. WO2004/005601A1.

In some embodiments, the polyethylene compositions produced by thisinvention may be blended with one or more other polymers, including butnot limited to, thermoplastic polymer(s) and/or elastomer(s).

By “thermoplastic polymer(s)” is meant a polymer that can be melted byheat and then cooled without appreciable change in solid-stateproperties before and after heating. Thermoplastic polymers typicallyinclude, but are not limited to, polyolefins, polyamides, polyesters,polycarbonates, polysulfones, polyacetals, polylactones,acrylonitrile-butadiene-styrene resins, polyphenylene oxide,polyphenylene sulfide, styrene-acrylonitrile resins, styrene maleicanhydride, polyimides, aromatic polyketones, or mixtures of two or moreof the above. Preferred polyolefins include, but are not limited to,polymers comprising one or more linear, branched or cyclic C₂ to C₄₀olefins, preferably polymers comprising ethylene copolymerized with oneor more C₃ to C₄₀ olefins, preferably a C₃ to C₂₀ alpha olefin, morepreferably C₃ to C₁₀ alpha-olefins. A particularly preferred example ispolybutene. The most preferred polyolefin is polypropylene. Otherpreferred polyolefins include, but are not limited to, polymerscomprising ethylene including but not limited to ethylene copolymerizedwith a C₃ to C₄₀ olefin, preferably a C₃ to C₂₀ alpha olefin, morepreferably propylene, butene, hexene, and/or octene.

By “elastomers” is meant all natural and synthetic rubbers, includingthose defined in ASTM D1566. Examples of preferred elastomers include,but are not limited to, ethylene propylene rubber, ethylene propylenediene monomer rubber, styrenic block copolymer rubbers (including SEBS,SI, SIS, SB, SBS, SIBS and the like, where S=styrene, EB=randomethylene+butene, I=isoprene, and B=butadiene), butyl rubber, halobutylrubber, copolymers of isobutylene and para-alkylstyrene, halogenatedcopolymers of isobutylene and para-alkylstyrene, natural rubber,polyisoprene, copolymers of butadiene with acrylonitrile,polychloroprene, alkyl acrylate rubber, chlorinated isoprene rubber,acrylonitrile chlorinated isoprene rubber, polybutadiene rubber (bothcis and trans).

In another embodiment, the blend comprising the modifier may further becombined with one or more polymers polymerizable by a high-pressure freeradical process, polyvinylchloride, polybutene-1, isotactic polybutene,ABS resins, block copolymer, styrenic block copolymers, polyamides,polycarbonates, PET resins, crosslinked polyethylene, copolymers ofethylene and vinyl alcohol (EVOH), polymers of aromatic monomers such aspolystyrene, poly-1 esters, polyacetal, polyvinylidine fluoride,polyethylene glycols and/or polyisobutylene.

Tackifiers may be blended with the ethylene compositions of thisinvention. Examples of useful tackifiers include, but are not limitedto, aliphatic hydrocarbon resins, aromatic modified aliphatichydrocarbon resins, hydrogenated polycyclopentadiene resins,polycyclopentadiene resins, gum rosins, gum rosin esters, wood rosins,wood rosin esters, tall oil rosins, tall oil rosin esters, polyterpenes,aromatic modified polyterpenes, terpene phenolics, aromatic modifiedhydrogenated polycyclopentadiene resins, hydrogenated aliphatic resin,hydrogenated aliphatic aromatic resins, hydrogenated terpenes andmodified terpenes, and hydrogenated rosin esters. In some embodiments,the tackifier is hydrogenated. In other embodiments the tackifier isnon-polar. Non-polar means that the tackifier is substantially free ofmonomers having polar groups. Preferably, the polar groups are notpresent; however, if they are, preferably they are present at not morethan 5 wt %, preferably not more than 2 wt %, even more preferably nomore than 0.5 wt %, based upon the weight of the tackifier. In someembodiments, the tackifier has a softening point (Ring and Ball, asmeasured by ASTM E-28) of 80° C. to 140° C., preferably 100° C. to 130°C. The tackifier, if present, is typically present at about 1 wt % toabout 50 wt %, based upon the weight of the blend, more preferably 10 wt% to 40 wt %, even more preferably 20 wt % to 40 wt %.

Preferably, however, tackifier is not present, or if present, is presentat less than 10 wt %, preferably less than 5 wt %, more preferably atless than 1 wt %.

Blending and Processing

The compositions and blends described herein may be formed usingconventional equipment and methods, such as by dry blending theindividual components and subsequently melt mixing in a mixer, or bymixing the components together directly in a mixer, such as, forexample, a Banbury mixer, a Haake mixer, a Brabender internal mixer, ora single or twin-screw extruder, which may include a compoundingextruder and a side-arm extruder used directly downstream of apolymerization process. Additionally, additives may be included in theblend, in one or more components of the blend, and/or in a productformed from the blend, such as a film, as desired. Such additives arewell known in the art, and can include, for example: fillers;antioxidants (e.g. hindered phenolics such as IRGANOX™ 1010 or IRGANOX™1076 available from Ciba-Geigy); phosphites (e.g. IRGAFOS™ 168 availablefrom Ciba-Geigy); anti-cling additives; tackifiers, such as polybutenes,terpene resins, aliphatic and aromatic hydrocarbon resins, alkali metaland glycerol stearates and hydrogenated rosins; UV stabilizers; heatstabilizers; antiblocking agents; release agents; anti-static agents;pigments; colorants; dyes; waxes; silica; fillers; talc; and the like.

The polymers suitable for use in the present invention can be in anyphysical form when used to blend with the modifier of the invention. Inone embodiment, reactor granules, defined as the granules of polymerthat are isolated from the polymerization reactor prior to anyprocessing procedures, are used to blend with the modifier of theinvention. The reactor granules typically have an average diameter offrom 50 μm to 10 mm in one embodiment, and from 10 μm to 5 mm in anotherembodiment. In another embodiment, the polymer is in the form ofpellets, such as, for example, having an average diameter of from 1 mmto 10 mm that are formed from melt extrusion of the reactor granules.

The components of the present invention can be blended by any suitablemeans, and are typically blended to yield an intimately mixedcomposition which may be a homogeneous, single phase mixture. Forexample, they may be blended in a static mixer, batch mixer, extruder,or a combination thereof, that is sufficient to achieve an adequatedispersion of modifier in the polymer.

The mixing step may involve first dry blending using, for example, atumble blender, where the polymer and modifier are brought into contactfirst, without intimate mixing, which may then be followed by meltblending in an extruder. Another method of blending the components is tomelt blend the polymer pellets with the modifier directly in an extruderor batch mixer. It may also involve a “master batch” approach, where thefinal modifier concentration is achieved by combining neat polymer withan appropriate amount of modified polymer that had been previouslyprepared at a higher modifier concentration. The mixing step may takeplace as part of a processing method used to fabricate articles, such asin the extruder on an injection molding machine or blown-film line orfiber line.

In a preferred aspect of the invention, the ethylene polymer andmodifier are “melt blended” in an apparatus such as an extruder (singleor twin screw) or batch mixer. The ethylene polymer may also be “dryblended” with the modifier using a tumbler, double-cone blender, ribbonblender, or other suitable blender. In yet another embodiment, theethylene polymer and modifier are blended by a combination ofapproaches, for example a tumbler followed by an extruder. A preferredmethod of blending is to include the final stage of blending as part ofan article fabrication step, such as in the extruder used to melt andconvey the composition for a molding step like injection molding or blowmolding. This could include direct injection of the modifier into theextruder, either before or after the polyethylene is fully melted.Extrusion technology for polyethylene is described in more detail in,for example, PLASTICS EXTRUSION TECHNOLOGY p. 26-37 (Friedhelm Hensen,ed. Hanser Publishers 1988).

In another aspect of the invention, the polyethylene composition may beblended in solution by any suitable means, by using a solvent thatdissolves both components to a significant extent. The blending mayoccur at any temperature or pressure where the modifier and the ethylenepolymer remain in solution. Preferred conditions include blending athigh temperatures, such as 10° C. or more, preferably 20° C. or moreover the melting point of the ethylene polymer. Such solution blendingwould be particularly useful in processes where the ethylene polymer ismade by solution process and the modifier is added directly to thefinishing train, rather than added to the dry polymer in anotherblending step altogether. Such solution blending would also beparticularly useful in processes where the ethylene polymer is made in abulk or high pressure process where both the polymer and the modifierwere soluble in the monomer. As with the solution process, the modifieris added directly to the finishing train rather than added to the drypolymer in another blending step altogether.

Thus, in the cases of fabrication of articles using methods that involvean extruder, such as injection molding or blow molding, any means ofcombining the polyethylene and modifier to achieve the desiredcomposition serve equally well as fully formulated pre-blended pellets,since the forming process includes a re-melting and mixing of the rawmaterial; example combinations include simple blends of neat polymerpellets and modifier, neat polymer granules and modifier, neat polymerpellets and pre-blended pellets, and neat polymer granules andpre-blended pellets. Here, “pre-blended pellets” means pellets of apolyethylene composition comprising ethylene polymer and modifier atsome concentration. In the process of compression molding, however,little mixing of the melt components occurs, and pre-blended pelletswould be preferred over simple blends of the constituent pellets (orgranules) and modifier. Those skilled in the art will be able todetermine the appropriate procedure for blending of the polymers tobalance the need for intimate mixing of the component ingredients withthe desire for process economy.

Applications

The enhanced properties of the polyethylene compositions describedherein are useful in a wide variety of applications, includingtransparent articles such as cook and storage ware, and in otherarticles such as furniture, automotive components, toys, sportswear,medical devices, sterilizable medical devices and sterilizationcontainers, nonwoven fibers and fabrics and articles therefrom such asdrapes, gowns, filters, hygiene products, diapers, and films, orientedfilms, sheets, tubes, pipes and other items where softness, high impactstrength, and impact strength below freezing is important.

Additional examples of desirable articles of manufacture made fromcompositions of the invention include films, sheets, fibers, woven andnonwoven fabrics, automotive components, furniture, sporting equipment,food storage containers, transparent and semi-transparent articles,toys, tubing and pipes, sheets, packaging, bags, sacks, coatings, caps,closures, crates, pallets, cups, non-food containers, pails, insulation,and medical devices. Further examples include automotive components,wire and cable jacketing, pipes, agricultural films, geomembranes, toys,sporting equipment, medical devices, casting and blowing of packagingfilms, extrusion of tubing, pipes and profiles, sporting equipment,outdoor furniture (e.g. garden furniture), playground equipment, boatand water craft components, and other such articles. In particular, thecompositions are suitable for automotive components such as bumpers,grills, trim parts, dashboards, instrument panels, exterior door andhood components, spoiler, wind screen, hub caps, mirror housing, bodypanel, protective side molding, and other interior and externalcomponents associated with automobiles, trucks, boats, and othervehicles.

Other useful articles and goods may be formed economically by thepractice of our invention including: crates, containers, packaging,labware, such as roller bottles for culture growth and media bottles,office floor mats, instrumentation sample holders and sample windows;liquid storage containers such as bags, pouches, and bottles for storageand IV infusion of blood or solutions; packaging material includingthose for any medical device or drugs including unit-dose or otherblister or bubble pack as well as for wrapping or containing foodpreserved by irradiation. Other useful items include medical tubing andvalves for any medical device including infusion kits, catheters, andrespiratory therapy, as well as packaging materials for medical devicesor food which is irradiated including trays, as well as stored liquid,particularly water, milk, or juice, containers including unit servingsand bulk storage containers as well as transfer means such as tubing,pipes, and such.

Fabrication of these articles may be accomplished by injection molding,extrusion, thermoforming, blow molding, rotational molding(rotomolding), fiber spinning, spin bonding or melt blown bonding suchas for non-woven fabrics, film blowing, stretching for oriented films,casting such as for films (including use of chill rolls), profiledeformation, coating (film, wire, and cable), compression molding,calendering, foaming, laminating, transfer molding, cast molding,pultrusion, protrusion, draw reduction, and other common processingmethods, or combinations thereof, such as is known in the art anddescribed in, for example, PLASTICS PROCESSING (Radian Corporation,Noyes Data Corp. 1986). Use of at least thermoforming or filmapplications allows for the possibility of and derivation of benefitsfrom uniaxial or biaxial orientation. Sufficient mixing should takeplace to assure that an intimately mixed, preferably uniform blend willbe produced prior to conversion into a finished product.

Adhesives

The polymers of this invention or blends thereof can be used asadhesives, either alone or combined with tackifiers. Preferredtackifiers are described above. The tackifier is typically present atabout 1 wt % to about 50 wt %, based upon the weight of the blend, morepreferably 10 wt % to 40 wt %, even more preferably 20 wt % to 40 wt %.Other additives, as described above, may also be added.

The adhesives of this invention can be used in any adhesive application,including but not limited to, disposables, packaging, laminates,pressure sensitive adhesives, tapes labels, wood binding, paper binding,non-wovens, road marking, reflective coatings, and the like. In apreferred embodiment the adhesives of this invention can be used fordisposable diaper and napkin chassis construction, elastic attachment indisposable goods converting, packaging, labeling, bookbinding,woodworking, and other assembly applications. Particularly, preferredapplications include: baby diaper leg elastic, diaper frontal tape,diaper standing leg cuff, diaper chassis construction, diaper corestabilization, diaper liquid transfer layer, diaper outer coverlamination, diaper elastic cuff lamination, feminine napkin corestabilization, feminine napkin adhesive strip, industrial filtrationbonding, industrial filter material lamination, filter mask lamination,surgical gown lamination, surgical drape lamination, and perishableproducts packaging.

Films

The compositions described above and the blends thereof may be formedinto monolayer or multilayer films. These films may be formed by any ofthe conventional techniques known in the art including extrusion,co-extrusion, extrusion coating, lamination, blowing and casting. Thefilm may be obtained by the flat film or tubular process which may befollowed by orientation in a uniaxial direction or in two mutuallyperpendicular directions in the plane of the film. One or more of thelayers of the film may be oriented in the transverse and/or longitudinaldirections to the same or different extents. This orientation may occurbefore or after the individual layers are brought together. For examplea polyethylene layer can be extrusion coated or laminated onto anoriented polypropylene layer or the polyethylene and polypropylene canbe coextruded together into a film then oriented.

Likewise, oriented polypropylene could be laminated to orientedpolyethylene, or oriented polyethylene could be coated ontopolypropylene then optionally the combination could be oriented evenfurther. Typically the films are oriented in the Machine Direction (MD)at a ratio of up to 15, preferably between 5 and 7, and in theTransverse Direction (TD) at a ratio of up to 15 preferably 7 to 9.However in another embodiment the film is oriented to the same extent inboth the MD and TD directions.

In multilayer constructions, the other layer(s) may be any layertypically included in multilayer film structures. For example the otherlayer or layers may be:

-   1. Polvolefins. Preferred polyolefins include homopolymers or    copolymers of C₂ to C₄₀ olefins, preferably C₂ to C₂₀ olefins,    preferably a copolymer of an alpha-olefin and another olefin or    alpha-olefin (ethylene is defined to be an alpha-olefin for purposes    of this invention). Preferably homopolyethylene, homopolypropylene,    propylene copolymerized with ethylene and or butene, ethylene    copolymerized with one or more of propylene, butene or hexene, and    optional dienes. Preferred examples include thermoplastic polymers    such as ultra low density polyethylene, very low density    polyethylene, linear low density polyethylene, low density    polyethylene, medium density polyethylene, high density    polyethylene, polypropylene, isotactic polypropylene, highly    isotactic polypropylene, syndiotactic polypropylene, random    copolymer of propylene and ethylene and/or butene and/or hexene,    elastomers such as ethylene propylene rubber, ethylene propylene    diene monomer rubber, neoprene, and blends of thermoplastic polymers    and elastomers, such as, for example, thermoplastic elastomers and    rubber toughened plastics.-   2. Polar polymers. Preferred polar polymers include homopolymers and    copolymers of esters, amides, acetates, anhydrides, copolymers of a    C₂ to C₂₀ olefin, such as ethylene and/or propylene and/or butene    with one or more polar monomers such as acetates, anhydrides,    esters, alcohol, and or acrylics. Preferred examples include    polyesters, polyamides, ethylene vinyl acetate copolymers, and    polyvinyl chloride.-   3. Cationic polymers. Preferred cationic polymers include polymers    or copolymers of geminally disubstituted olefins, alpha-heteroatom    olefins and/or styrenic monomers. Preferred geminally disubstituted    olefins include isobutylene, isopentene, isoheptene, isohexane,    isooctene, isodecene, and isododecene. Preferred alpha-heteroatom    olefins include vinyl ether and vinyl carbazole, preferred styrenic    monomers include styrene, alkyl styrene, para-alkyl styrene,    alpha-methyl styrene, chloro-styrene, and bromo-para-methyl styrene.    Preferred examples of cationic polymers include butyl rubber,    isobutylene copolymerized with para methyl styrene, polystyrene, and    poly-alpha-methyl styrene.-   4. Miscellaneous. Other preferred layers can be paper, wood,    cardboard, metal, metal foils (such as aluminum foil and tin foil),    metallized surfaces, glass (including silicon oxide (SiO_(x))    coatings applied by evaporating silicon oxide onto a film surface),    fabric, spunbonded fibers, and non-wovens (particularly    polypropylene spun bonded fibers or non-wovens), and substrates    coated with inks, dyes, pigments, and the like.

The films may vary in thickness depending on the intended application;however, films of a thickness from 1 μm to 250 μm are usually suitable.Films intended for packaging are usually from 10 to 60 micron thick. Thethickness of the sealing layer is typically 0.2 μm to 50 μm. There maybe a sealing layer on both the inner and outer surfaces of the film orthe sealing layer may be present on only the inner or the outer surface.Films intended for heavier use, such as geomembranes), can be from 25 μmto 260 μm thick, preferably from 25 μm to 130 μm thick, preferably from50 μm to 110 μm thick.

Additives such as block, antiblock, antioxidants, pigments, fillers,processing aids, UV stabilizers, neutralizers, lubricants, surfactantsand/or nucleating agents may also be present in one or more than onelayer in the films. Preferred additives include silicon dioxide,titanium dioxide, polydimethylsiloxane, talc, dyes, wax, calciumsterate, carbon black, low molecular weight resins and glass beads,preferably these additives are present at from 0.1 ppm to 1000 ppm.

In another embodiment, one more layers may be modified by coronatreatment, electron beam irradiation, gamma irradiation, or microwaveirradiation. In a preferred embodiment, one or both of the surfacelayers is modified by corona treatment.

The films described herein may also comprise from 5 wt % to 60 wt %,based upon the weight of the polymer and the resin, of a hydrocarbonresin. The resin may be combined with the polymer of the seal layer(s)or may be combined with the polymer in the core layer(s). The resinpreferably has a softening point above 100° C., even more preferablyfrom 130° C. to 180° C. Preferred hydrocarbon resins include thosedescribed above. The films comprising a hydrocarbon resin may beoriented in uniaxial or biaxial directions to the same or differentdegrees. For more information on blends of tackifiers and modifiersuseful herein, see U.S. Application No. 60/617,594, filed Oct. 8, 2004.

The films described above may be used as stretch and/or cling films.Stretch/cling films are used in various bundling, packaging andpalletizing operations. To impart cling properties to, or improve thecling properties of a particular film, a number of well-known tackifyingadditives have been utilized. Common tackifying additives includepolybutenes, terpene resins, alkali metal stearates and hydrogenatedrosins and rosin esters. The cling properties of a film can also bemodified by the well-known physical process referred to as coronadischarge. Some polymers (such as ethylene methyl acrylate copolymers)do not need cling additives and can be used as cling layers withouttackifiers. Stretch/cling films may comprise a slip layer comprising anysuitable polyolefin or combination of polyolefins such as polyethylene,polypropylene, copolymers of ethylene and propylene, and polymersobtained from ethylene and/or propylene copolymerized with minor amountsof other olefins, particularly C₄ to C₁₂ olefins. Particularly,preferred is linear low density polyethylene (LLDPE). Additionally, theslip layer may include one or more anticling (slip and/or antiblock)additives which may be added during the production of the polyolefin orsubsequently blended in to improve the slip properties of this layer.Such additives are well-known in the art and include, for example,silicas, silicates, diatomaceous earths, talcs, and various lubricants.These additives are preferably utilized in amounts ranging from about100 ppm to about 20,000 ppm, more preferably between about 500 ppm toabout 10,000 ppm, by weight based upon the weight of the slip layer. Theslip layer may, if desired, also include one or more other additives asdescribed above.

In a preferred embodiment, films prepared from the compositionsdescribed herein have improved bubble stability compared to the ethylenecopolymers of the compositions alone as determined by reduced gaugevariation, e.g. a gauge variation of 10% or less, preferably 8% or less,preferably 5% or less.

In a preferred embodiment, films prepared from the compositionsdescribed herein have excellent optical properties, such as a haze (ASTMD1003) of 20 or less, preferably 15 or less, preferably 10 or less.

Molded and Extruded Products

The polyethylene composition described above may also be used to preparemolded products in any molding process, including but not limited to,injection molding, gas-assisted injection molding, extrusion blowmolding, injection blow molding, injection stretch blow molding,compression molding, rotational molding, foam molding, thermoforming,sheet extrusion, and profile extrusion. The molding processes are wellknown to those of ordinary skill in the art.

The compositions described herein may be shaped into desirable end usearticles by any suitable means known in the art. Thermoforming, vacuumforming, blow molding, rotational molding, slush molding, transfermolding, wet lay-up or contact molding, cast molding, cold forming,matched-die molding, injection molding, spray techniques, profileco-extrusion, or combinations thereof are typically used methods.

Thermoforming is a process of forming at least one pliable plastic sheetinto a desired shape. An embodiment of a thermoforming sequence isdescribed, however, this should not be construed as limiting thethermoforming methods useful with the compositions of this invention.First, an extrudate film of the composition of this invention (and anyother layers or materials) is placed on a shuttle rack to hold it duringheating. The shuttle rack indexes into the oven which pre-heats the filmbefore forming. Once the film is heated, the shuttle rack indexes backto the forming tool. The film is then vacuumed onto the forming tool tohold it in place and the forming tool is closed. The forming tool can beeither “male” or “female” type tools. The tool stays closed to cool thefilm and the tool is then opened. The shaped laminate is then removedfrom the tool. Thermoforming is accomplished by vacuum, positive airpressure, plug-assisted vacuum forming, or combinations and variationsof these, once the sheet of material reaches thermoforming temperatures,typically of from 140° C. to 185° C. or higher. A pre-stretched bubblestep is used, especially on large parts, to improve materialdistribution. In one embodiment, an articulating rack lifts the heatedlaminate towards a male forming tool, assisted by the application of avacuum from orifices in the male forming tool. Once the laminate isfirmly formed about the male forming tool, the thermoformed shapedlaminate is then cooled, typically by blowers. Plug-assisted forming isgenerally used for small, deep drawn parts. Plug material, design, andtiming can be critical to optimization of the process. Plugs made frominsulating foam avoid premature quenching of the plastic. The plug shapeis usually similar to the mold cavity, but smaller and without partdetail. A round plug bottom will usually promote even materialdistribution and uniform side-wall thickness. For a semicrystallinepolymer, fast plug speeds generally provide the best materialdistribution in the part. The shaped laminate is then cooled in themold. Sufficient cooling to maintain a mold temperature of 30° C. to 65°C. is desirable. The part is below 90° C. to 100° C. before ejection inone embodiment. The shaped laminate is then trimmed of excess laminatematerial.

Blow molding is another suitable forming means, which includes injectionblow molding, multi-layer blow molding, extrusion blow molding, andstretch blow molding, and is especially suitable for substantiallyclosed or hollow objects, such as, for example, gas tanks and otherfluid containers. Blow molding is described in more detail in, forexample, CONCISE ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING(Jacqueline I. Kroschwitz, ed., John Wiley & Sons 1990).

In yet another embodiment of the formation and shaping process, profileco-extrusion can be used. The profile co-extrusion process parametersare as above for the blow molding process, except the die temperatures(dual zone top and bottom) range from 150° C. to 235° C., the feedblocks are from 90° C. to 250° C., and the water cooling tanktemperatures are from 10° C. to 40° C.

One embodiment of an injection molding process is described as follows.The shaped laminate is placed into the injection molding tool. The moldis closed and the substrate material is injected into the mold. Thesubstrate material has a melt temperature between 180° C. and 300° C. inone embodiment, and from 200° C. and 250° C. in another embodiment, andis injected into the mold at an injection speed of between 2 and 10seconds. After injection, the material is packed or held at apredetermined time and pressure to make the part dimensionally andaesthetically correct. Typical time periods are from 5 to 25 seconds andpressures from 1,000 kPa to 15,000 kPa. The mold is cooled between 10°C. and 70° C. to cool the substrate. The temperature will depend on thedesired gloss and appearance. Typical cooling time is from 10 to 30seconds, depending in part on the thickness. Finally, the mold is openedand the shaped composite article ejected.

Likewise, molded articles may be fabricated by injecting molten polymerblend into a mold that shapes and solidifies the molten polymer intodesirable geometry and thickness of molded articles. A sheet may be madeeither by extruding a substantially flat profile from a die, onto achill roll, or alternatively by calendering. Sheet will generally beconsidered to have a thickness of from 10 mils to 100 mils (254 μm to2540 μm), although sheet may be substantially thicker. Tubing or pipemay be obtained by profile extrusion for uses in medical, potable water,land drainage applications or the like. The profile extrusion processinvolves the extrusion of molten polymer through a die. The extrudedtubing or pipe is then solidified by chill water or cooling air into acontinuous extruded article. The tubing will generally be in the rangeof from 0.31 cm to 2.54 cm in outside diameter, and have a wallthickness in the range of from 254 μm to 0.5 cm. The pipe will generallybe in the range of from 2.54 cm to 254 cm in outside diameter, and havea wall thickness in the range of from 0.5 cm to 15 cm. Sheet made fromthe products of an embodiment of a version of the present invention maybe used to form containers. Such containers may be formed bythermoforming, solid phase pressure forming, stamping and other shapingtechniques. Sheets may also be formed to cover floors or walls or othersurfaces.

In an embodiment of the thermoforming process, the oven temperature isbetween 160° C. and 195° C., the time in the oven between 10 and 20seconds, and the die temperature, typically a male die, between 10° C.and 71° C. The final thickness of the cooled (room temperature), shapedlaminate is from 10 μm to 6000 μm in one embodiment, from 200 μm to 6000μm in another embodiment, and from 250 μm to 3000 μm in yet anotherembodiment, and from 500 μm to 1550 μm in yet another embodiment, adesirable range being any combination of any upper thickness limit withany lower thickness limit.

In an embodiment of the injection molding process, wherein a substratematerial is injection molded into a tool including the shaped laminate,the melt temperature of the substrate material is between 190° C. and255° C. in one embodiment, and between 210° C. and 250° C. in anotherembodiment, the fill time from 2 to 10 seconds in one embodiment, from 2to 8 seconds in another embodiment, and a tool temperature of from 25°C. to 65° C. in one embodiment, and from 27° C. and 60° C. in anotherembodiment. In a desirable embodiment, the substrate material is at atemperature that is hot enough to melt any tie-layer material or backinglayer to achieve adhesion between the layers.

In yet another embodiment of the invention, the compositions of thisinvention may be secured to a substrate material using a blow moldingoperation. Blow molding is particularly useful in such applications formaking closed articles, such as fuel tanks and other fluid containers,playground equipment, outdoor furniture and small enclosed structures.

It will be understood by those skilled in the art that the stepsoutlined above may be varied, depending upon the desired result. Forexample, the extruded sheet of the compositions of this invention may bedirectly thermoformed or blow molded without cooling, thus skipping acooling step. Other parameters may be varied as well in order to achievea finished composite article having desirable features.

In another embodiment, this invention relates to:

1. A branched polyethylene modifier comprising at least 50 mol %ethylene, one or more C₄ to C₄₀ comonomers, and a polyene having atleast two polymerizable bonds, wherein said branched polyethylenemodifier has: a) a g′_(vis) of 0.70 or less; b) an Mw of 100,000 g/molor more; c) an Mw/Mn of 4.0 or more; d) a shear thinning ratio of 110 ormore; e) a melt strength of 10 cN or more, f) a complex viscosity at 0.1rad/sec at 190° C. of at least the branched modifier may have, 000 Pa·s;and g) has a phase angle of Z° or less where Z=138.3 G*^((−0.142)),where G* is the complex modulus reported in Pascals measured at 190° C.and the phase angle units are reported in degrees, wherein the G* isfrom 1,000 to 1,000,000 Pa.2. The modifier of paragraph 1, wherein the comonomer is present at from0.5 to 30 mol %.3. The modifier of paragraph 1 or 2, wherein the polyene is present atfrom 0.001 to 10 mol %.4. The modifier of paragraph 1, 2, or 3, wherein the modifier has ag′_((Zave)) of 0.70 or less.5. The modifier of paragraph 1, 2, 3, or 4, wherein the modifier has astrain-hardening ratio of 2 or greater.6. The modifier of any of paragraphs 1 to 5, wherein the C₄ to C₄₀comonomers are one or more C₆ to C₄₀ alpha olefin comonomers.7. The modifier of any of paragraphs 1 to 6, wherein the modifier has aphase angle at complex shear modulus G*=100,000 Pa of at least 300.8. The modifier of any of paragraphs 1 to 7, wherein the C₄ to C₄₀comonomers are one or more hexene, butene, or octene.9. The modifier of any of paragraphs 1 to 8, wherein the polyene isselected from the group consisting of: 1,4-pentadiene, 1,5-hexadiene,1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, and1,13-tetradecadiene; tetrahydroindene; norbomadiene also known asbicyclo-(2.2.1)-hepta-2,5-diene; dicyclopentadiene; 5-vinyl-2-norbomene;1,4-cyclohexadiene; 1,5-cyclooctadiene; and 1,7-cyclododecadiene.10. The modifier of any of paragraphs 1 to 9, wherein the modifier is anethylene, octene, 1,9-decadiene copolymer.11. A blend comprising:1) the modifier of any of paragraphs 1 to 10 and/or a branchedpolyethylene modifier comprising at least 50 mol % ethylene, one or moreC₄ to C₄₀ comonomers, and a polyene having at least two polymerizablebonds, wherein said branched polyethylene modifier has:a) a g′_(vis) of 0.70 or less; b) an Mw of 100,000 g/mol or more; c) anMw/Mn of 4.0 or more; d) a shear thinning ratio of 110 or more; e) amelt strength of 10 cN or more, f) a complex viscosity at 0.1 rad/sec at190° C. of at least 120,000 Pa·s; and g) a phase angle of Z° or lesswhere Z=138.3 G*^((−0.142)), where G* is the complex modulus reported inPascals measured at 190° C. and the phase angle units are reported indegrees, wherein the G* is from 1,000 to 1,000,000 Pa; and h) a complexviscosity ratio of Y or more, where Y=−0.27*(Log η*_(matrix))+1.4, andthe complex viscosity ratio is defined to be (Log η*_(modifier) minusLog η*_(matrix)) divided by (Log η*_(matrix)), wherein η*_(modifier) isthe complex viscosity of the modifier measured at 0.1 rad/sec and 190°C., and η*_(matrix) is the complex viscosity of the polyethylene of step2) below measured at 0.1 rad/sec and 190° C.; and2) polyethylene having a density of 0.88 g/cc or more and an Mw of20,000 g/mol or more, and preferably a g′_(vis) of 0.97 or more, whereinthe melt strength ratio is Q or more, whereQ=0.0805[(η*modifier−η*_(matrix))/(η*_(matrix))]+0.5, wherein 1*modifieris the complex viscosity of the modifier measured at 0.158 rad/sec and190° C., and η*_(matrix) is the complex viscosity of the polyethylenemeasured at 0.158 rad/sec and 190° C.; and the melt strength ratio isdefined to be [(MS_(blend)−MS_(matrix))/(MS_(matrix))], where MS_(blend)is the melt strength of the blend, MS_(matrix) is the melt strength ofthe polyethylene.12. The composition of paragraph 11, wherein the complex viscosity at0.1 sec⁻¹ of the branched polyethylene modifier is at least 320% greaterthan (preferably at least 2000% greater than) the complex viscosity at0.1 sec⁻¹ of the polyethylene prior to combination with the branchedpolyethylene modifier.13. The composition of paragraph 11 or 12, wherein the branchedpolyethylene modifier is present at 0.5 wt % to 10 wt %.14. The composition of paragraph 11, 12, or 13, wherein the polyethylenecomprises a copolymer of ethylene and one or more C₃ to C₂₀ alphaolefinsand has an Mw of 20,000 to 1,000,000 g/mol.15. The composition of paragraph 11, 12, 13, or 14, wherein thepolyethylene has a density of 0.91 to 0.96 g/cm³.16. The composition of paragraph 11, 12, 13, 14, or 15, wherein thebranched polyethylene modifier is present at from 0.1 wt % to 99.5 wt %(based upon the weight of the blend); and the polyethylene has acomposition distribution breadth index of 60% or more and a density of0.90 g/cc or more.17. The blend composition of any of paragraphs 11 to 16, which has astrain hardening ratio of greater than 1.5.18. The blend of any of paragraphs 11 to 17, wherein the C₄ to C₄₀comonomers of the modifier are one or more C₆ to C₄₀ alpha olefincomonomers.19. The composition of any of paragraphs 1 to 10, wherein the branchedpolyethylene modifier has an Mw of 20,000 g/mol or more.20. The blend of any of paragraphs 11 to 18 wherein the blend has anelasticity ratio of Z* or more, where Z*=0.009*(δ_(matrix))+0.05, wherethe elasticity ratio is defined to be[(δ_(matrix)−δ_(modifier))/(δ_(matrix))], where δ_(matrix) is the phaseangle of the linear polyethylene measured at a complex modulus of100,000 Pa, δ_(modifier) is the phase angle of the branched modifier ata complex modulus of 100,000 Pa, where phase angle is determined asdescribed below, preferably Z*=0.008*(δ_(matrix))+0.14, preferablyZ*=0.0079*(δ_(matrix))+0.1318. 21. The blend of any of paragraphs 11 to18 wherein the blend has a melt strength ratio of T or more, whereT=0.1.6762[(η*_(blend) minus η*_(matrix)) divided by (η*_(matrix))]−5,where η*_(blend) is the complex viscosity of the blend measured at 0.158rad/sec and 190° C., and η*_(matrix) is the complex viscosity of thelinear polyethylene measured at 0.158 rad/sec and 190° C.; and the ratioof melt strength to viscosity is defined to be melt strength ratio isdefined to be [(MS_(blend) minus MS_(matrix)) divided by (MS_(matrix))],where MS_(blend) is the melt strength of the composition, MS_(matrix) isthe melt strength of the linear polyethylene, melt strength is reportedin cN and measured according to the procedure in the Test Methodssection below, preferably T=0.1.6762[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+0, preferably T=0.1.6762[(η*_(blend) minusη*_(matrix)) divided by (η*_(matrix))]+5, preferablyT=0.1.6762[(η*_(blend) minus η*_(matrix)) divided by (η*_(matrix))]+10,preferably T=0.1.6762[(η*_(blend) minus η*_(matrix)) divided by(η*_(matrix))]+15, preferably T=0.1.6762[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+16.153. 22. The blend of any of paragraphs 11to 18 wherein the blend has a melt strength ratio of T or more, where Tis equal to 2.1957[(η*_(blend) minus η*_(matrix)) divided by(η*_(matrix))]+30, preferably T=2.1957[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]+40, preferably T=2.1957[(η*_(blend) minusη*_(matrix)) divided by (η*_(matrix))]+50, preferablyT=2.1957[(η*_(blend) minus η*_(matrix)) divided by (η*_(matrix))]+60.23. A film or foam comprising the composition of any of paragraphs 1 to10 or 19.24. A film or foam comprising the composition of any of paragraphs 11 to18, or 20-22.

Test Methods

Melt Index (MI, also referred to as 12) is measured according to ASTMD1238 at 190° C., under a load of 2.16 kg unless otherwise noted. Theunits for MI are g/10 min or dg/min.

High Load Melt Index (HLMI, also referred to as 121) is the melt flowrate measured according to ASTM D-1238 at 190° C., under a load of 21.6kg. The units for HLMI are g/10 min or dg/min.

Melt Index Ratio (MIR) is the ratio of the high load melt index to themelt index, or 121/12.

Density is measured by density-gradient column, as described in ASTMD1505, on a compression-molded specimen that has been slowly cooled toroom temperature (i.e. over a period of 10 minutes or more) and allowedto age for a sufficient time that the density is constant within+/−0.001 g/cm³. The units for density are g/cm³.

Gauge, reported in mils, was measured using a Measuretech Series 200instrument. The instrument measures film thickness using a capacitancegauge. For each film sample, ten film thickness data points weremeasured per inch of film as the film was passed through the gauge in atransverse direction. From these measurements, an average gaugemeasurement was determined and reported. Coefficient of variation (GaugeCOV) is used to measure the variation of film thickness in thetransverse direction. The Gauge COV is defined as a ratio of thestandard deviation to the mean of film thickness.

Elmendorf Tear, reported in grams (g) or grams per mil (g/mil), wasmeasured as specified by ASTM D-1922.

Tensile Strength at Yield, Tensile Strength at Break, Ultimate TensileStrength and Tensile Strength at 50%, 100%, and/or 200% Elongation weremeasured as specified by ASTM D-882.

Tensile Peak Load was measured as specified by ASTM D-882.

Tensile Energy, reported in inch-pounds (in-lb), was measured asspecified by ASTM D-882.

Elongation at Yield and Elongation at Break, reported as a percentage(%), were measured as specified by ASTM D-882.

1% Secant Modulus (M), reported in pounds per square inch (lb/in² orpsi), was measured as specified by ASTM D-882.

Haze, reported as a percentage (%), was measured as specified by ASTMD-1003.

Gloss, a dimensionless number, was measured as specified by ASTM D-2457at 45 degrees.

Dart Drop Impact or Dart Drop Impact Strength (DIS), reported in grams(g) and/or grams per mil (g/mil), was measured as specified by ASTMD-1709, method A, unless otherwise specified.

Peak Puncture Force, reported in pounds (lb) and/or pounds per mil(lb/mil), was determined according to ASTM D-3763.

Puncture Break Energy, reported in inch-pounds (in-lb) and/orinch-pounds per mil (in-lb/mil), was determined according to ASTMD-3763.

“Melt strength” is defined as the force required to draw a moltenpolymer extrudate at a rate of 12 mm/s² and at an extrusion temperatureof 190° C. until breakage of the extrudate whereby the force is appliedby take up rollers. The polymer is extruded at a velocity of 0.33 mm/sthrough an annular die of 2 mm diameter and 30 mm length. Melt strengthvalues reported herein are determined using a Gottfert Rheotens testerand are reported in centi-Newtons (cN). Additional experimentalparameters for determining the melt strength are listed in Table 1. Forthe measurements of melt strength, the resins were stabilized with 500ppm of Irganox 1076 and 1500 ppm of Irgafos168.

TABLE 1 Melt Strength test parameters Acceleration 12 mm/s² Temperature190° C. Piston diameter 12 mm Piston speed 0.178 mm/s Die diameter 2 mmDie length 30 mm Shear rate at the die 40.05 s⁻¹ Strand length 100.0 mmVo (velocity at die exit) 10.0 mm/s

Dynamic shear melt rheological data was measured with an AdvancedRheometrics Expansion System (ARES) using parallel plates (diameter=25mm) in a dynamic mode under nitrogen atmosphere. For all experiments,the rheometer was thermally stable at 190° C. for at least 30 minutesbefore inserting compression-molded sample of resin onto the parallelplates. To determine the samples viscoelastic behavior, frequency sweepsin the range from 0.01 to 385 rad/s were carried out at a temperature of190° C. under constant strain. Depending on the molecular weight andtemperature, strains of 10% and 15% were used and linearity of theresponse was verified. A nitrogen stream was circulated through thesample oven to minimize chain extension or cross-linking during theexperiments. All the samples were compression molded at 190° C. and nostabilizers were added. A sinusoidal shear strain is applied to thematerial. If the strain amplitude is sufficiently small the materialbehaves linearly. It can be shown that the resulting steady-state stresswill also oscillate sinusoidally at the same frequency but will beshifted by a phase angle δ with respect to the strain wave. The stressleads the strain by δ. For purely elastic materials δ=0° (stress is inphase with strain) and for purely viscous materials, δ=90° (stress leadsthe strain by 90° although the stress is in phase with the strain rate).For viscoelastic materials, 0<δ<90. The shear thinning slope (STS) wasmeasured using plots of the logarithm (base ten) of the dynamicviscosity versus logarithm (base ten) of the frequency. The slope is thedifference in the log(dynamic viscosity) at a frequency of 100 s⁻¹ andthe log(dynamic viscosity) at a frequency of 0.01 s⁻¹ divided by 4.Dynamic viscosity is also referred to as complex viscosity or dynamicshear viscosity.

The dynamic shear viscosity (q*) versus frequency (o) curves were fittedusing the Cross model (see, for example, C. W. Macosco, RHEOLOGY:PRINCIPLES, MEASUREMENTS, AND APPLICATIONS, Wiley-VCH, 1994):

$\eta^{*} = \frac{\eta_{0}}{1 + ({\lambda\omega})^{1 - n}}$

The three parameters in this model are: η₀, the zero-shear viscosity; λ,the average relaxation time; and n, the power-law exponent. Thezero-shear viscosity is the value at a plateau in the Newtonian regionof the flow curve at a low frequency, where the dynamic viscosity isindependent of frequency. The average relaxation time corresponds to theinverse of the frequency at which shear-thinning starts. The power-lawexponent describes the extent of shear-thinning, in that the magnitudeof the slope of the flow curve at high frequencies approaches 1−n on alog(η*)−log(ω) plot. For Newtonian fluids, n=1 and the dynamic complexviscosity is independent of frequency. For the polymers of interesthere, n<1, so that enhanced shear-thinning behavior is indicated by adecrease in n (increase in 1-n).

The transient uniaxial extensional viscosity was measured using aSER-2-A Testing Platform available from Xpansion Instruments LLC,Tallmadge, Ohio, USA. The SER Testing Platform was used on a RheometricsARES-LS (RSA3) strain-controlled rotational rheometer available from TAInstruments Inc., New Castle, Del., USA. The SER Testing Platform isdescribed in U.S. Pat. No. 6,578,413 & 6,691,569, which are incorporatedherein for reference. A general description of transient uniaxialextensional viscosity measurements is provided, for example, in “Strainhardening of various polyolefins in uniaxial elongational flow”, TheSociety of Rheology, Inc., J. Rheol., 47(3), p. 619-630 (2003); and“Measuring the transient extensional rheology of polyethylene meltsusing the SER universal testing platform”, The Society of Rheology,Inc., J. Rheol., 49(3), p. 585-606 (2005), incorporated herein forreference Strain hardening occurs when a polymer is subjected touniaxial extension and the transient extensional viscosity increasesmore than what is predicted from linear viscoelastic theory. Strainhardening is observed as an abrupt upswing of the extensional viscosityin the transient extensional viscosity vs. time plot. A strain hardeningratio (SHR) is used to characterize the upswing in extensional viscosityand is defined as the ratio of the maximum transient extensionalviscosity over three times the value of the transient zero-shear-rateviscosity at the same strain. Strain hardening is present in thematerial when the ratio is greater than 1.

Comonomer content (such as for butene, hexene and octene) was determinedvia FTIR measurements according to ASTM D3900 (calibrated versus ¹³CNMR). A thin homogeneous film of polymer, pressed at a temperature ofabout 150° C., was mounted on a Perkin Elmer Spectrum 2000 infraredspectrophotometer. The weight percent of copolymer is determined viameasurement of the methyl deformation band at ^(˜)1375 cm-1. The peakheight of this band is normalized by the combination and overtone bandat ^(˜)4321 cm-1, which corrects for path length differences.

Peak melting point, Tm, (also referred to as melting point), peakcrystallization temperature, Tc, (also referred to as crystallizationtemperature), glass transition temperature (Tg), heat of fusion (AHf orHf), and percent crystallinity were determined using the following DSCprocedure according to ASTM D3418-03. Differential scanning calorimetric(DSC) data were obtained using a TA Instruments model Q200 machine.Samples weighing approximately 5-10 mg were sealed in an aluminumhermetic sample pan. The DSC data were recorded by first graduallyheating the sample to 200° C. at a rate of 10° C./minute. The sample waskept at 200° C. for 2 minutes, then cooled to −90° C. at a rate of 10°C./minute, followed by an isothermal for 2 minutes and heating to 200°C. at 10° C./minute. Both the first and second cycle thermal events wererecorded. Areas under the endothermic peaks were measured and used todetermine the heat of fusion and the percent of crystallinity. Thepercent crystallinity is calculated using the formula, [area under themelting peak (Joules/gram)/B (Joules/gram)]* 100, where B is the heat offusion for the 100% crystalline homopolymer of the major monomercomponent. These values for B are to be obtained from the PolymerHandbook, Fourth Edition, published by John Wiley and Sons, New York1999, provided; however, that a value of 189 J/g (B) is used as the heatof fusion for 100% crystalline polypropylene, a value of 290 J/g is usedfor the heat of fusion for 100% crystalline polyethylene. The meltingand crystallization temperatures reported here were obtained during thesecond heating/cooling cycle unless otherwise noted.

For polymers displaying multiple endothermic and exothermic peaks, allthe peak crystallization temperatures and peak melting temperatures werereported. The heat of fusion for each endothermic peak was calculatedindividually. The percent crystallinity is calculated using the sum ofheat of fusions from all endothermic peaks. Some of the polymer blendsproduced show a secondary melting/cooling peak overlapping with theprincipal peak, which peaks are considered together as a singlemelting/cooling peak. The highest of these peaks is considered the peakmelting temperature/crystallization point. For the amorphous polymers,having comparatively low levels of crystallinity, the meltingtemperature is typically measured and reported during the first heatingcycle. Prior to the DSC measurement, the sample was aged (typically byholding it at ambient temperature for a period of 2 days) or annealed tomaximize the level of crystallinity.

Polymer molecular weight (weight-average molecular weight, Mw,number-average molecular weight, Mn, and Z-averaged molecular weight,Mz) and molecular weight distribution (Mw/Mn) are determined usingSize-Exclusion Chromatography. Equipment consists of a High TemperatureSize Exclusion Chromatograph (either from Waters Corporation or PolymerLaboratories), with a differential refractive index detector (DRI), anonline light scattering detector, and a viscometer (SEC-DRI-LS-VIS). Forpurposes of the claims, SEC-DRI-LS-VIS shall be used. Three PolymerLaboratories PLgel 10 mm Mixed-B columns are used. The nominal flow rateis 0.5 cm³/min and the nominal injection volume is 300 μL. The varioustransfer lines, columns and differential refractometer (the DRIdetector) are contained in an oven maintained at 135° C. Solvent for theSEC experiment is prepared by dissolving 6 grams of butylated hydroxytoluene as an antioxidant in 4 liters of reagent grade 1,2,4trichlorobenzene (TCB). The TCB mixture is then filtered through a 0.7μm glass pre-filter and subsequently through a 0.1 μm Teflon filter. TheTCB is then degassed with an online degasser before entering the SEC.

Polymer solutions are prepared by placing dry polymer in a glasscontainer, adding the desired amount of TCB, then heating the mixture at160° C. with continuous agitation for about 2 hours. All quantities aremeasured gravimetrically. The TCB densities used to express the polymerconcentration in mass/volume units are 1.463 g/ml at room temperatureand 1.324 g/ml at 135° C. The injection concentration can range from 1.0to 2.0 mg/ml, with lower concentrations being used for higher molecularweight samples.

Prior to running each sample the DRI detector and the injector arepurged. Flow rate in the apparatus is then increased to 0.5 ml/minute,and the DRI allowed to stabilize for 8 to 9 hours before injecting thefirst sample. The LS laser is turned on 1 to 1.5 hours before runningsamples.

The concentration, c, at each point in the chromatogram is calculatedfrom the DRI signal after subtracting the prevailing baseline, IDRI,using the following equation:

c=K _(DRI) I _(DRI)/(dn/dc)

where K_(DRI) is a constant determined by calibrating the DRI, and(dn/dc) is the same as described below for the LS analysis. Theprocesses of subtracting the prevailing baseline (i.e. backgroundsignal) and setting integration limits that define the starting andending points of the chromatogram are well known to those familiar withSEC analysis. Units on parameters throughout this description of the SECmethod are such that concentration is expressed in g/cm³, molecularweight is expressed in g/mole, and intrinsic viscosity is expressed indL/g.

The light scattering detector is a Wyatt Technology High Temperaturemini-DAWN. The polymer molecular weight, M, at each point in thechromatogram is determined by analyzing the LS output using the Zimmmodel for static light scattering (M. B. Huglin, LIGHT SCATTERING FROMPOLYMER SOLUTIONS, Academic Press 1971)

$\frac{K_{o}c}{\Delta \; {R(\theta)}} = {\frac{1}{{MP}(\theta)} + {2A_{2}c}}$

Here, ΔR(θ) is the measured excess Rayleigh scattering intensity atscattering angle θ, c is the polymer concentration determined from theDRI analysis, A₂ is the second virial coefficient, P(θ) is the formfactor for a monodisperse random coil (described in the abovereference), and K₀ is the optical constant for the system:

$K_{o} = \frac{4\pi^{2}{n^{2}\left( {{dn}\text{/}{dc}} \right)}^{2}}{\lambda^{4}N_{A}}$

in which N_(A) is Avogadro's number, and (dn/dc) is the refractive indexincrement for the system. The refractive index, n=1.500 for TCB at 135°C. and X=690 nm. In addition, A₂=0.0015 and (dn/dc)=0.104 forpolyethylene in TCB at 135° C.; both parameters may vary with averagecomposition of an ethylene copolymer. Thus, the molecular weightdetermined by LS analysis is calculated by solving the above equationsfor each point in the chromatogram; together these allow for calculationof the average molecular weight and molecular weight distribution by LSanalysis.

A high temperature Viscotek Corporation viscometer is used, which hasfour capillaries arranged in a Wheatstone bridge configuration with twopressure transducers. One transducer measures the total pressure dropacross the detector, and the other, positioned between the two sides ofthe bridge, measures a differential pressure. The specific viscosity forthe solution flowing through the viscometer at each point in thechromatogram, (η_(s))_(i), is calculated from the ratio of theiroutputs. The intrinsic viscosity at each point in the chromatogram,[η]_(i), is calculated by solving the following equation (for thepositive root) at each point i:

(η_(s))_(i) =c _(i)[η]_(i)+0.3(c _(i)[η]_(i))²

where c_(i) is the concentration at point i as determined from the DRIanalysis.

The branching index (g′_(vis)) is calculated using the output of theSEC-DRI-LS-VIS method (described above) as follows. The averageintrinsic viscosity, [η]_(avg), of the sample is calculated by:

$\lbrack\eta\rbrack_{avg} = \frac{\Sigma \; {c_{i}\lbrack\eta\rbrack}_{i}}{\Sigma \; c_{i}}$

where the summations are over the chromatographic slices, i, between theintegration limits. The branching index g′ is defined as:

$g_{vis}^{\prime} = \frac{\lbrack\eta\rbrack_{avg}}{{kM}_{v}^{\alpha}}$

where the Mark-Houwink parameters k and α are given by k=0.000579 forpolyethylene homopolymer and α=0.695 for all polyethylene polymers. Forethylene copolymers, k decreases with increasing comonomer content. Myis the viscosity-average molecular weight based on molecular weightsdetermined by LS analysis.

Experimental and analysis details not described above, including how thedetectors are calibrated and how to calculate the composition dependenceof Mark-Houwink parameters and the second-virial coefficient, aredescribed by T. Sun, P. Brant, R. R. Chance, and W. W. Graessley(Macromolecules, 2001 volume 34(19), p. 6812-6820).

Proton NMR spectra were collected using a 500 MHz Varian pulsed fouriertransform NMR spectrometer equipped with a variable temperature protondetection probe operating at 120° C. The polymer sample is dissolved in1,1,2,2-tetrachloroethane-d2 (TCE-d2) and transferred into a 5 mm glassNMR tube. Typical acquisition parameters are sweep width=10 KHz, pulsewidth=30 degrees, acquisition time=2 s, acquisition delay=5 s and numberof scans=120. Chemical shifts are determined relative to the TCE-d2signal which is set to 5.98 ppm.

The chain end unsaturations are measured as follows. The vinylresonances of interest are between from about 5.0 to 5.1 ppm (VRA), thevinylidene resonances between from about 4.65 to 4.85 ppm (VDRA), thevinylene resonances from about 5.31 to 5.55 ppm (VYRA), thetrisubstituted unsaturated species from about 5.11 to 5.30 ppm (TSRA)and the aliphatic region of interest between from about 0 to 2.1 ppm(IA). The number of vinyl groups/1000 Carbons is determined from theformula: (VRA*500)/((IA+VRA+VYRA+VDRA)/2)+TSRA). Likewise, the number ofvinylidene groups/1000 Carbons is determined from the formula:(VDRA*500)/((IA+VRA+VYRA+VDRA)/2)+TSRA), the number of vinylenegroups/1000 Carbons from the formula(VYRA*500)/((IA+VRA+VYRA+VDRA)/2)+TSRA) and the number of trisubstitutedgroups from the formula (TSRA*1000)/((IA+VRA+VYRA+VDRA)/2)+TSRA). VRA,VDRA, VYRA, TSRA and IA are the integrated normalized signal intensitiesin the chemical shift regions defined above.

In conducting the ¹³C NMR investigations, samples are prepared by addingabout 0.3 g sample to approximately 3 g of tetrachloroethane-d2 in a 10mm NMR tube. The samples are dissolved and homogenized by heating thetube and its contents to 150° C. The data are collected using a Varianspectrometer, with corresponding ¹H frequencies of either 400 or 700 MHz(in event of conflict, 700 MHz shall be used). The data are acquiredusing nominally 4000 transients per data file with a about a 10 secondpulse repetition delay. To achieve maximum signal-to-noise forquantitative analysis, multiple data files may be added together. Thespectral width was adjusted to include all the NMR resonances ofinterest and FIDs were collected containing a minimum of 32K datapoints. The samples are analyzed at 120° C. in a 10 mm broad band probe.

Where applicable, the properties and descriptions below are intended toencompass measurements in both the machine and transverse directions.Such measurements are reported separately, with the designation “MD”indicating a measurement in the machine direction, and “TD” indicating ameasurement in the transverse direction.

EXAMPLES

The present invention, while not meant to be limited by, may be betterunderstood by reference to the following examples and tables.

Examples 1 to 4

Four branched modifiers were produced in a 1-liter autoclave reactoroperated in a slurry process. The reactor system was equipped with astirrer, an external water/steam jacket for temperature control, aregulated supply of dry nitrogen, ethylene, propylene, hydrogen and aseptum inlet for introduction of other solvents, catalysts, liquidmonomer, and scavenger solutions. The reactor was first washed using hottoluene and then dried and degassed thoroughly prior to use. All thesolvents and monomers were purified by passing through a 1-liter basicalumina column activated at 600° C., followed by a column of molecularsieves activated at 600° C. or Selexsorb CD column prior to transferringinto the reactor.

Dimethylsilyl-bis-(tetrahydroindenyl) zirconium dichloride was used asmetallocene Catalyst A. The metallocene was supported on silicaparticles according to the procedure described in U.S. Pat. No.6,476,171 B1. In brief, a solution of 1300 ml of 30 wt % alumoxane (MAO)in toluene as determined by reference to the total Al content, which mayinclude unhydrolyzed TMA was charged to a two gallon (7.57 Liter),jacketed glass-walled reactor, equipped with a helical ribbon blenderand an auger-type shaft. 2080 ml of toluene was added and stirred. Asuspension of 31.5 g metallocene catalyst in 320 ml of toluene purchasedfrom Albemarle Labs, was cannulated to the reactor. An additional bottleof dry toluene (250 ml) was used to rinse solid metallocene crystalsinto the reactor by cannula under nitrogen pressure. The mixture wasallowed to stir at 69° F. (20.6° C.) for one hour, before beingtransferred to a four-liter Erlenmeyer flask under nitrogen. 1040 gramsof silica (Davison MS 948, 1.65 ml/g pore volume) was charged to thereactor. Half of the solution from the 4 liter Erlenmeyer flask was thentransferred back to the 2 gallon (7.57 liter) stirred glass reactor. Thereaction temperature rose from 70° F. (21.1° C.) to 100° F. (37.8° C.)in a five minute exotherm. The balance of the solution in the 4 literErlenmeyer was subsequently added back to the glass reactor, and stirredtwenty minutes. Then, toluene was added (273 ml, 238 g) to dilute theactive catalyst slurry, and stirred an additional twenty-five minutes. 7grams of Antistat AS-990, a surface modifier made from ethoxylatedstearylamine sold by Witco Chemical Corp. (7 g in 73 ml toluene), wascannulated to the reactor and the slurry mixed for thirty minutes.Removal of solvent commenced by reducing pressure to less than 18 inchesof mercury (457 mmHg) while feeding a small stream of nitrogen into thebottom of the reactor and raising the temperature from 74° F. (23.3° C.)to 142° F. (61.1° C.) over a period of one hour. Then five additionalhours of drying at 142° F. (61.1° C.) to 152° F. (66.7° C.) and vacuumwhich ranged from 5 inches to 22 inches Hg (127 to 559 mmHg) were usedto dry the support and yield 1709.0 g of free-flowing active supportedcatalyst material. Head space gas chromatograph (HSGC) measurementsshowed 13,000 weight parts per million (1.3 wt %) of residual toluene. Asecond drying step under stronger vacuum conditions resulted in HSGCanalysis measurement of residual toluene at 0.18%. 1,9-decadiene wasused as the polymerizable diene. The 1,9-decadiene was obtained fromSigma-Aldrich and was purified by first passing through an aluminacolumn activated at high temperature under nitrogen, followed by amolecular sieve activated at high temperature under nitrogen.

In polymerization run, 2 ml of triisobutyl aluminum (TIBAL) (25 wt % inhexane, purchased from Sigma-Aldrich) solution was first added to thereactor. In succession, 400 ml of isohexane (diluent), 1-hexene, 1,9decadiene and hydrogen were added into the reactor. All of these wereconducted at room temperature. The mixture was then stirred and heatedto a desired temperature. The supported catalyst was cannulated into thereactor using about 200 ml of solvent, followed immediately by ethyleneaddition. The ethylene was fed on demand to maintain a relative constantreactor pressure during the polymerization reaction. The ethylenepressure reported in Table 2 was the difference between the reactorpressure immediately before ethylene addition and ethylene feed pressureduring the polymerization. The ethylene consumption was monitored duringthe reaction using a mass flow meter. The polymerization reaction wasterminated when desired amount of polymer was produced. Thereafter, thereactor was cooled down and unreacted monomer and diluent were vented tothe atmosphere. The resulting mixture, containing mostly diluent,polymer and unreacted monomers, was collected in a collection box andfirst air-dried in a hood to evaporate most of the solvent, and thendried in a vacuum oven at a temperature of about 90° C. for about 12hours. Details of the experimental conditions, catalysts employed andthe properties of the resultant polymer are listed in Table 2. Each runwas repeated 3-5 times to produce enough material for applicationevaluation.

TABLE 2 Branched modifier produced in a slurry process Modifier # 1 2 34 Catalyst Cata- Cata- Cata- Cata- lyst A lyst A lyst A lyst A Catalystamount (mg) 120 120 120 120 Reaction temp. (° C.) 80 80 80 80 Reactiontime (min) 60 60 60 60 Hydrogen (mmol) 5 5 5 5 Ethylene feed pressure(psi) 214 214 214 214 1-hexene (ml) 2.0 20 20 20 1,9 decadiene (ml) 0.050.05 0.02 0.01 Ethylene content(wt %) 96.0 Yield (g) 42 49 43 40 Tc (°C.) 113.1 110.2 113.5 113.5 Tm (° C.) 126.9 127.3 126.8 127.1 Heat offusion (J/g) 190.7 194.9 193.3 209.0 Ethylene content (wt %) 96 Mn_DRI(g/mol) 6,704 Mw_DRI (g/mol) 94,866 Mz_DRI (g/mol) 627,782 Mn_LS (g/mol)17,607 Mw_LS (g/mol) 111,717 Mz_LS (g/mol) 795,054 g′_(vis) 0.969 I2(dg/min) 0.76 0.41 3.30 5.68 I21 (dg/min) 53.42 33.55 129.89 192.91 MIR69.93 81.82 39.36 33.96 Complex viscosity @ 0.01 27053 2247 3284 818rad/sec (Pa · s) Complex viscosity @ 398 194 16 21 13 rad/sec (Pa · s)Complex viscosity @ 100 384.4 31.4 42.2 24.7 rad/sec (Pa · s) Complexviscosity@ 0.1 9283.0 749.7 1117.9 350.5 rad/sec (Pa · s)

For the measurement of branching index, g′_(vis), the Mark-Houwinkparameters, k, are corrected for comonomer content and type withouttaking into account of diene content.

The complex viscosity of the branched modifier polymer produced inExamples 1 to 4 was measured at temperature 190° C. over an angularfrequency ranging from 0.01 to 398 rad/s. Significant shear thinning wasobserved. The ratio of complex viscosity at a frequency of 0.01 rad/s tothe complex viscosity at a frequency of 398 rad/s is 139, 141, 160, and62 for materials produced in Example 1, 2, 3, and 4, respectively. Thecomplex viscosity profiles are shown in FIG. 2. Examples 1 to 4 haveshear thinning slope, the slope of the log (complex viscosity) versuslog (frequency) curve, of −0.466, −0.468, −0.479, and −0.389,respectively. The more negative this slope, the faster the dynamicviscosity decreases as the frequency increases. These types of polymerare easily processed in high shear rate fabrication methods, such asinjection molding. Large negative shear thinning slopes occur whenpolymers are highly branched. Significant shear thinning is alsoreflected in the high values of MIR.

When the phase angle is plotted versus frequency for material made inExamples 1 to 4, the phase angles are nearly independent of frequencyand a plateau is observed. The phase angels vary between 40 to 60degrees over a frequency range from 0.01 to 398 rad/sec. This is asignature of a gel-like relaxation behavior and the critical relaxationexponent can be calculated as the ratio of the phase angle of theplateau divided by 90 degrees. The critical relaxation exponents forExamples 1 to 4 are less than 0.63. Linear polyolefins do not haveplateaus in their plots of phase angle versus frequency. According toGarcia-Franco, et al, Macromolecules, 34(10), 2001, p. 3115-3117, thelower the critical relaxation exponent, the more extensive the longchain branches in the sample. The critical relaxation exponents observedfor the branched modifier of this invention are lower than any reportedin this paper.

The phase angle is the inverse tangent of the loss modulus divided bythe storage modulus. For linear polymer chains the polymer melt is fullyrelaxed at small frequencies or long relaxation times; the storagemodulus is much smaller than the loss modulus and the phase angles are90 degrees. For the branched modifier of Examples 1 to 4 the lossmodulus is comparable to the storage modulus even at a frequency of 0.1rad/s. The chains are unable to relax, because of the presence ofsignificant amounts of branching.

The transient extensional viscosity of the modifier produced in Example1 was measured at a temperature of 150° C. and strain rate of 1 sec⁻¹. Astrain hardening ratio of 50.8 was observed.

Examples 5 to 13

Branched modifiers in Examples 5 to 13 were made in a continuousstirred-tank reactor operated in a solution process. The reactor was a0.5-liter stainless steel autoclave reactor and was equipped with astirrer, a water cooling/steam heating element with a temperaturecontroller and a pressure controller. Solvents and comonomers were firstpurified by passing through a three-column purification system. Thepurification system consisted of an Oxiclear column (Model #RGP-R1-500from Labclear) followed by a 5A and a 3A molecular sieve column.Purification columns were regenerated periodically whenever there wasevidence of lower activity of polymerization. Both the 3A and 5Amolecular sieve columns were regenerated in-house under nitrogen at aset temperature of 260° C. and 315° C., respectively. The molecularsieve material was purchased from Aldrich. Oxiclear column wasregenerated in the original manufacture. Ethylene was delivered as a gassolubilized in the chilled solvent/monomer mixture. The purifiedsolvents and monomers were then chilled to about −15° C. by passingthrough a chiller before being fed into the reactor through a manifold.Solvent and monomers were mixed in the manifold and fed into the reactorthrough a single tube. All liquid flow rates were measured usingBrooksfield mass flow controller.

The metallocenes were pre-activated with an activator of N,N-dimethylanilinium tetrakis (heptafluoro-2-naphthyl) borate at a molar ratio ofabout 1:1 in toluene. The preactivated catalyst solution was kept in aninert atmosphere with <1.5 ppm water content and was fed into thereactor by a metering pump through a separated line. Catalyst andmonomer contacts took place in the reactor.

As an impurity scavenger, 200 ml of tri-n-octyl aluminum (TNOA) (25 wt %in hexane, Sigma Aldrich) was diluted in 22.83 kilogram of isohexane.The TNOA solution was stored in a 37.9-liter cylinder under nitrogenblanket. The solution was used for all polymerization runs until about90% of consumption, and then a new batch was prepared. The feed rates ofthe TNOA solution were adjusted in a range from 0 (no scavenger) to 4 mlper minute to achieve a maximum catalyst activity.

The reactor was first prepared by continuously N₂ purging at a maximumallowed temperature, then pumping isohexane and scavenger solutionthrough the reactor system for at least one hour. Monomers and catalystsolutions were then fed into the reactor for polymerization. Once theactivity was established and the system reached equilibrium, the reactorwas lined out by continuing operation of the system under theestablished condition for a time period of at least five times of meanresidence time prior to sample collection. The resulting mixture,containing mostly solvent, polymer and unreacted monomers, was collectedin a collection box. The collected samples were first air-dried in ahood to evaporate most of the solvent, and then dried in a vacuum ovenat a temperature of about 90° C. for about 12 hours. The vacuum ovendried samples were weighed to obtain yields. All the reactions werecarried out at a pressure of about 2 MPa.

1,9 decediene was diluted with isohexane and fed into the reactor usinga metering pump. Both ethylene (bis indenyl) zirconium dimethyl(catalyst B) and rac-dimethylsilylbis(indenyl)zirconium dimethyl(Catalyst C) were preactivated with N,N-dimethyl anilinium tetrakis(heptafluoro-2-naphthyl) borate. The polymerization process conditionand some characterization data are listed in Table 3. For eachpolymerization run, the catalyst feed rate and scavenger fed rate wereadjusted to achieve a desired conversion listed in Table 3.

TABLE 3 Branched modifier produced in a solution process Modifier # 5 67 8 Reaction temperature (° C.) 140 137 120 130 ethylene feed rate(slpm) 8 8 8 8 1-hexene feed rate (g/min) 3 3 3 3 1,9 decadiene feedrate (ml/min) 0.0476 0.0488 0.024 0.0488 Catalyst Catalyst B Catalyst BCatalyst B Catalyst B Yield (gram/min) 8.97 9.43 10.14 9.68 Conversion(%) 74.5% 78.2% 84.2% 80.4% Catalyst efficiency (g poly/g catalyst)538200 565500 608600 580923 Ethylene content (wt %) 90.8 87.1 85.2 87.2Density (g/cm3) 0.9215 Tc (° C.) 94.4 86.7 83.5 87.4 Tm (° C.) 110.7103.2 98.4 102.4 Heat of fusion (J/g) 136.9 118.2 101.7 116.1 Mn_DRI(g/mol) 12,180 12,029 16,650 9,559 Mw_DRI (g/mol) 90,693 44,213 87,96576,219 Mz_DRI (g/mol) 463,907 85,791 276,492 284,371 Mn_LS (g/mol)27,617 14,563 24,995 21,955 Mw_LS (g/mol) 174,260 36,154 95,374 100,539Mz_LS (g/mol) 1,434,765 78,146 315,225 579,821 g′_(vis) 0.513 0.88 0.7180.696 I2 (dg/min) <0.1 81.6 1.1 1.8 I21 (dg/min) 29.4 58.9 93.6 MIR 53.650.9 Complex viscosity @ 0.01 43128 2497 22262 12201 rad/sec (Pa · s)Complex viscosity @ 398 232 89 376 265 rad/sec (Pa · s) Complexviscosity @ 100 521.5 134.2 842.8 569.6 rad/sec (Pa · s) Complexviscosity @ 0.1 20162.0 173.8 16847.5 9893.2 rad/sec (Pa · s) Phaseangle at G* = 100,000 38.2 39.8 Pa (degree) Modifier # 9 10 11 12 13Reaction temperature (° C.) 130 130 130    130 130 ethylene feed rate(slpm) 8 8 8     8 8 1-hexene feed rate (g/min) 2.5 2 4     3 3 1,9decadiene feed rate (ml/min) 0.0488 0.0488 0.024      0.0488 0.0488Catalyst Catalyst B Catalyst B Catalyst C Catalyst C Catalyst C Yield(gram/min) 9.85 9.81 9.64     10.58 9.78 Conversion (%) 85.3% 88.8%73.8%    88% 81.2 Catalyst efficiency (g poly/g catalyst) 537,182535,000 825,905 906,944 1,048,784 Ethylene content (wt %) 87.2 88.7 85.1   83.8 87.4 Tc (° C.) 88.3 91.7 75.4    80.9 83.4 Tm (° C.) 103.7 106.795.0    97.7 102.7 Heat of fusion (J/g) 112.8 123.0 97.7    100.0 114.2Mn_DRI (g/mol) 17,728 10,786 25,011  25,347 31,746 Mw_DRI (g/mol)101,280 51,964 87,916 128,813 181,281 Mz_DRI (g/mol) 433,198 105,012243,019 504,459 729,567 Mn_LS (g/mol) 21,483 22,247 27,775  39,46071,110 Mw_LS (g/mol) 174,433 55,077 105,137 225,011 390,378 Mz_LS(g/mol) 1,336,719 116,596 398,179 1,350,319   2,248,953 g′_(vis) 0.5930.853 0.739      0.574 0.43 I2 (dg/min) 12.2 6.4 0.4    <0.1 <0.1 I21(dg/min) 447.8 265.8 22.3    12.2 2.1 MIR 36.8 41.5 59.5 Complexviscosity @ 0.01 1540 1810 75288   81589 436290 rad/sec (Pa · s) Complexviscosity @ 398 193 256 549.3 rad/sec (Pa · s) Complex viscosity @ 100352.6 506.5 1265    899.1 1304 rad/sec (Pa · s) Complex viscosity @ 0.11214.2 2494.0 43220   37949 122420 rad/sec (Pa · s) Phase angle at G* =100,000 44.0 36.5    33 28 Pa (degree)

The complex viscosity of the branched modifier polymer produced inExamples 5 to 10 was measured at a temperature of 190° C. over anangular frequency ranging from 0.01 to 398 rad/s. Significant shearthinning was observed. The ratio of the complex viscosity at a frequencyof 0.01 rad/s to the complex viscosity at a frequency of 398 rad/s was186, 59.2, and 8 for materials produced in Examples 5, 7, and 9respectively. The shear thinning slope, the slope of the log (complexviscosity) versus log (frequency) curve, for material produced inExamples 5, 7, and 9 were −0.494, −0.385, and −0.196, respectively.Significant shear thinning was also reflected in the high MIR values.The shear thinning for material produced in Examples 1 to 11 are greaterthan 53.9*I2^((−0.74)), where 12 is the melt index (190° C., 2.16 kg).

The transient extensional viscosity of the modifier produced in Example5 was measured at a temperature of 150° C. and a strain rate of 1 sec⁻¹.A strain hardening ratio of 7.3 was observed.

A melt strength value of 36.6 cN was observed for the modifier producedin Example 5.

The Van Gurp-Palmen plots of the branched modifiers produced in Examples5 to 10 are shown in FIG. 4 in comparison with the Exceed™ Polyethylene2018.

Exceed™ Polyethylene 2018 (“Exceed PE 2018”), an mLLDPE available fromExxonMobil Chemical Company (Houston, Tex.), has an MI of 2.0 dg/min anda density of 0.918 g/cm³.

Exceed™ Polyethylene 1018 (“Exceed PE 2018”), is an mLLDPE (metalloceneethylene/hexene copolymer) available from ExxonMobil Chemical Company(Houston, Tex.), having an MI of 1.0 dg/min and a density of 0.918g/cm³.

mPE-5 is an mLLDPE produced following the methods described in U.S. Pat.No. 6,956,088 having a density of 0.917 g/cm³ and melt index of 0.9dg/min and melt flow ratio of 24.4.

Polyethylene LD071.LR™ is an LDPE available from ExxonMobil ChemicalCompany (Houston, Tex.) having an MI of 0.70 dg/min and a density of0.924 g/cm³.

Enable™ 20-10 polyethylene is a metallocene ethylene-hexene copolymerhaving a melt index of 1.0 dg/min (ASTM D 1238, 2.16 kg, 190° C.) anddensity of 0.920 g/cc.

POL-A is a metallocene ethylene-hexene copolymer having a melt index of0.2 dg/min (ASTM D 1238, 2.16 kg, 190° C.), an MIR of 7, a peak meltingtemperature of 127° C. and a density of 0.940 g/cc.

The branched modifiers produced above were blended as a modifier withExceed PE 2018. The compounding of the modifier with Exceed PE 2018 wascarried out in a 1″ Haake twin screw extruder with an L/D of 15 followedby a strand pelletizer. The branched modifier was pre-mixed in solidstate with Exceed PE 2018 granules. A two-step compounding process wasemployed to ensure proper mixing. In the first compounding step, a blendof 60% of the modifier and 40% Exceed PE 2018 was produced in the twinscrew extruder. The extrudate was pelletized using a strand pelletizerand used as a master batch.

The master batch was then further diluted with additional ethylenepolymer to produce the inventive composition with desired concentrationof branched additives in the second compounding step. An antioxidantpackage was added into all the compounded compositions. The antioxidantconsists of 0.05 wt % of Irganox™ 1076 (available from Ciba SpecialtyChemicals Corporation, Tarrytown, N.Y.), 0.2 wt % of Weston™ 399(available from Chemtura) and 0.08 wt % of Dynamar™ FX592DA (availablefrom Dyneon LLC, Oakdale, Minn.). The concentration is the weightpercent of the final blend.

The compounding extrusion conditions are listed below.

Zone #1 180° C. Zone #2 185° C. Zone #3 190° C. Die (Zone #5) 195° C.Extruder Speed (rpm) 55

Examples 12 to 15

All of the blend compositions for Examples 12 to 15 were compounded withthe branched modifier and Exceed PE 2018 according the proceduredescribed above and contain the antioxidant package (0.33 wt %)described above.

TABLE 4 Example # 12 13 14 15 Exceed PE 2018 (wt %) 94.67 98.67 96.6794.67 Modifier # Modifier Modifier Modifier Modifier #1 #5 #5 #5Modifier (wt %) 5 1 3 5 Melt strength (cN) 3.19 1.42 1.77 2.82 Strainhardening ratio 1.7 1.5 2.7 2.6 Tc (° C.) 106.2 103.0 Tm (° C.) 120.0117.3

The complex viscosity profile of Example 15 is similar to that ofExceed™ 2018 polyethylene over an angular frequency range from 0.01 to398 rad/sec at a temperature of 190° C. No significant viscosity changewas observed when 5 wt % of the branched modifier #5 was blended withExceed™ 2018 polyethylene.

Strain hardening was observed for all the polyethylene compositionsproduced in Examples 12 to 15. The thermal properties of thepolyethylene compositions in the Examples 12 and 15 were measured usingDSC. The crystallization peak and melting peak from DSC for Example #15is almost overlapped with the peaks of Exceed 2018™ polyethylene. ForExample #12, a two-hump crystallization peak was observed. Both the Tcand Tm are higher than that for Exceed 2018™ polyethylene.

Some of the inventive compositions were tested for film applications.Blown films were made using Haake Rheomex 252P single screw extruder inconnection with a Brabender blown film die. The line contains a 1″single screw Haake extruder and a 1″ mono-layer blown film die. Thescrew is a 3:1 compression ratio metering screw with a Maddock typemixing section before the metering section. The die gap is 0.022 mm. Theextrusion die is also equipped with a cooling air ring on the outside ofthe die. The air ring is used to blow the air onto the film bubble tosolidify the film. There is an air orifice in the center of the die toprovide air to inflate the bubble. The line also contains two take-upnip rollers to pick up and collapse the film bubble. The film has 1.5mil gauge and 2.8 bubble blow-up ratio (BUR). The film bubble BUR andgauge are achieved by adjusting extruder speed, take-up speed and amountof air in the bubble. The specified process conditions are listed in thetable below.

Extrusion condition Unit Set point Zone #1 temperature ° C. 190 Zone #2temperature ° C. 195 Zone #3 temperature ° C. 190 Die (Zone #5)temperature ° C. 185 Extruder speed Rpm 33 Line speed ft/min 5.9 Filmgauge Mil 1.5 Layflat In 4.4

Tables 5 and 6 provide some properties of the films produced from theinventive composition. All film compositions contain 0.33 wt % of theantioxidant package described above, 5 wt % of modifier and 94.67 wt %of Exceed PE 2018 unless noted otherwise. Films with 100% Exceed PE 2018and 5 wt % of LD071.LR are comparative. All four modifier films (F01,F02, F03 and F04) exhibit significant improved haze property vs controlExceed 2018 (F06.) The haze level for these four modifier films issimilar to 5% LD071.LR film. Samples (F01, F02 and F04) also exhibit theimproved blown film processability characterized as TD film gaugecoefficient of variation in comparison to Exceed 2018. Theprocessability improvement for the modifier samples of F01, F02, and F04are similar to that of 5% LD071.LR.

TABLE 5 Summary of film properties Example # F01 F02 F03 F04 F05 F06Exceed PE 2018 94.67 wt % 94.67 wt % 94.67 wt % 94.67 wt % 94.67 wt %99.67 wt % Modifier # 1 (5 wt %) 2 (5 wt %) 3 (5 wt %) 4 (5 wt %)LD071.LR none (5 wt %) 1% Secant (psi) MD 31,946 29197 27319 2863428,940 24225 TD 33,323 28580 28540 27579 28,503 25273 Tensile YieldStrength (psi) MD 1344 1482 1422 1,304 1180 TD 1467 1428 1480 1,369 1332Elongation @ Yield (%) MD 6 7 7 6 5.5 TD 8 6 7 6 6.5 Tensile Strength(psi) MD 7219 7901 7421 7,564 7752 TD 7008 7572 7482 7,326 8155Elongation @ Break (%) MD 641 649 640 697 682 TD 637 652 649 664 682Elmendorf Tear MD (gms/mil) 281 320 347 327 259 349 TD (gms/mil) 447 458468 437 Total Haze (%) 16 17.7 16.0 16.2 17 48.2 Dart drop 246 225 210263 230 329 (gms/mil) Gauge COV 7.9% 5.4% 15.7% 6.8% 7.1% 11.6% Averageddie 2875 2906 3007 3015 2933 3007 pressure (psi). Averaged motor 43.540.9 45.2 45.0 36.5 45.6 load (N-m).

TABLE 6 Summary of film properties Example # F07 F08 F9 F10 Exceed PE2018 94.67 94.67 94.67 94.67 wt % wt % wt % wt % Modifier # 7 (5 8 (5 10(5 9 (5 wt %) wt %) wt %) wt %) 1% Secant (psi) MD 24373 24956 2262024007 TD 23660 24158 22256 21105 Tensile Yield Strength(psi) MD 12501294 1184 1207 TD 1303 1312 1257 1198 Elongation @ Yield (%) MD 8 6 7 7TD 6 6 7 7 Tensile Strength (psi) MD 7398 8082 7385 7420 TD 7637 74287148 7389 Elongation @ Break (%) MD 671 671 655 665 TD 652 658 651 667Elmendorf Tear MD (gms/mil) 361 338 368 351 TD (gms/mil) 416 427 438 431Total Haze (%) 39.3 14.6 40.1 38.3 Dart drop (gms/mil) 337 229 299 386Gauge COV 10.5% 13.3% 10.5% 13.3% Averaged die 2934 2982 3037 3031pressure (psi) Averaged motor 42.0 41.9 44.0 43.5 load (N-m).

Table 7 summarizes the film properties for the inventive composition ofthe branched modifier produced in Example #5 and Exceed PE 2018. All ofthe compositions contain 0.33 wt % of the antioxidant package. Theconcentration of the modifier produced in Example #5 is listed in thetable. Significant improvements in haze were observed for the films.F13, F14, and F15 with 1%, 3%, and 5% modifier were produced in Example5. The total haze is reduced from 48.2% for Exceed 2018 film to 10.7% of1% modifier and 7.3% for 5% modifier samples. The haze values for thesamples with 1-5% modifier produced in Example 5 is also considerablylower than 5% LD071.LR sample (F12.) The blown film processability,which is characterized by the TD gauge coefficient of variation (COV,)is significantly improved (lower COV) for 1%-5% modifier samples incomparison to Exceed PE 2018. Meanwhile the processability for themodifier addition samples is also superior to the blend with 5%LD071.LR. The film with 1% modifier (F13) retains the dart impactproperty of Exceed PE 2018, while LD071.LR film (F12) shows asubstantially reduced dart impact.

TABLE 7 Summary of film properties F11 Exceed F12 Film 2018 PE 5 wt %F13 F14 F15 Composition Unit (100%) LD071.LR 1 wt % of 5 3 wt % of 5 5wt % of 5 1% Secant - MD psi 24,225 28,940 25,406 26,088 27,811 1%Secant - TD psi 25,273 28,503 28,876 32,070 30,512 Elmendorf Tear - MDg/mil 349 259 341 320 314 Dart Drop, g/mil 329 230 345 205 206 TotalHaze % 48.2 17 10.7 7.5 7.3 Gauge COV 11.6% 7.1% 2.4% 4.8% 4.6% Averageddie Pressure psi 3007 2933 3117 3026 2899 (psi) Extruder Motor Load N-m45.6 36.5 45.6 44.3 41.1

Example 16

All of the blend compositions for Example 16 were compounded withbranched modifiers produced in examples #12 and #13 and various ethylenepolymers listed in Table 8 according to the procedure described aboveand contain the antioxidant package (0.33 wt %) described above. Thecompounded blends were tested for film application. Blown films weremade on a 2.5″ Gloucester blown film. The line is equipped with a 2.5″extruder and 6″ mono-layer circular blown film die. The extruder has 30L/D length and has a Barrier-Maddock screw. The die gap is 60 mil. Theextrusion die is also equipped with a Future Design dual lip cooling airring on the outside of the die. The air ring is used to blow the aironto the film bubble to solidify the film. There is an air orifice inthe center of the die to provide air to inflate the bubble. The linealso contains the bubble cage, up-nip and secondary nip devices andcollapsing frame to collapse the film bubble. The film has 1.0 mil gaugeand 2.5 bubble blow-up ratio (BUR). The film bubble BUR and gauge areachieved by adjusting extruder speed, take-up speed and amount of air inthe bubble. The specified process conditions are listed in the tablebelow.

Parameters Unit Set Point Set Point - Barrel #1 ° C. 310 Set Point -Barrel #2 ° C. 410 Set Point - Barrel #3 ° C. 375 Set Point - Barrel #4° C. 350 Set Point - Barrel #5 ° C. 350 Screen Changer ° C. 390 Adapter° C. 390 Rotator ° C. 390 Feed Throat ° C. 75 Lower Die ° C. 390 UpperDie ° C. 390 Inside Die ° C. 390 Upper Rotator ° C. 75 Standard Ratelbs/hr 188 Standard Line Speed ft/min 166 Film Gauge mil 1 Bubble BlowUp Ratio (BUR) 2.5 Film layflat in 23.6 Die Gap mil 60

The film compositions and characterization data are reported in Table 8.

TABLE 8 Summary of film composition and properties Example # F16 F17 F18F19 F20 Film composition Ethylene polymer Exceed Exceed Exceed ExceedExceed PE2018 PE2018 PE2018 PE1018 PE1018 Ethylene polymer (wt %) 99.6794.67 96.67 99.67 94.67 Branched modifier # none LD071.LR Modifier #13none LD071.LR Branched modifier (wt %) 5 3 5 Maximum rate Maximum linespeed (ft/min) 166 209.5 267.2 200 208 Maximum extrusion rate 188 247302 226 235 (lb/hr) Maximum line speed (%) 100 126 161 120 125 Diefactor (lb/hr-in-c) 10.0 13.1 16.0 12.0 12.5 1% secant (psi) MD 23,21625,194 26,552 24,049 28,503 TD 25,870 31,246 31,893 28,506 35,317Tensile properties Yield strength (psi) MD 1,162 1,353 1,285 1,361 1,421TD 1,219 1,453 1,416 1,374 1,603 Elongation @ yield (%) MD 6.2 7.5 6.77.1 6.1 TD 5.9 7.9 8.5 6.6 7.2 Tensile strength (psi) MD 7,168 7,6226,471 9,473 9,572 TD 6,980 7,135 7,111 8,308 8,052 Elongation @ break(%) MD 568 568 510 512 521 TD 697 706 703 665 662 Elmendorf tear(gms/mil) MD 336 142 193 250 136 TD 443 510 451 430 522 Haze (%) 47.14.2 4.1 16.5 2.4 Puncture Peak force (lbs/mil) 7.0 9.6 9.0 8.0 8.9 Breakenergy (in-lbs/mil) 18.68 27.52 25.09 21.2 19.2 Dart drop (gms/mil) 682412 426 911 647 Gauge (mils) Average 1.00 1.00 1.01 1.00 1.00 Low 0.900.87 0.93 0.93 0.93 High 1.12 1.17 1.12 1.08 1.11 Example # F21 F22 F23F24 Film composition Ethylene polymer Exceed mPE-5 mPE-5 mPE-5 PE1018Ethylene polymer (wt %) 97.67 99.67 94.67 97.67 Branched modifier #Modifier #12 none LD071.LR Modifier #12 Branched modifier (wt %) 9 5 2Maximum rate Maximum line speed (ft/min) 208 207 206 241 Maximumextrusion rate 235 234 233 273 (lb/hr) Maximum line speed (%) 125 124124 145 Die factor (lb/hr-in-c) 12.5 12.4 12.4 14.5 1% secant (psi) MD29,212 25,348 29,021 27,477 TD 34,717 29,900 38,739 34,952 Tensileproperties Yield Strength (psi) MD 1,461 1,304 1,389 1,365 TD 1,5741,442 1,626 1,472 Elongation @ yield (%) MD 6.6 6.8 6.2 6.3 TD 8.1 7.66.6 6.3 Tensile strength (psi) MD 8,462 9,708 8.738 8,358 TD 8,911 7,9937.574 8,490 Elongation @ break (%) MD 419 420 413 382 TD 694 661 638 675Elmendorf tear (gms/mil) MD 165 302 152 177 TD 491 460 513 554 Haze (%)2.4 10.0 3.7 4.3 Puncture Peak force (lbs/mil) 9.1 8.4 8.3 8.4 Breakenergy (in-lbs/mil) 23.8 21.1 17.7 20.7 Dart drop (gms/mil) 746 ≧1,3591,017 1,037 Gauge (mils) Average 1.02 1.01 1.02 1.02 Low 0.94 0.94 0.890.91 High 1.12 1.10 1.11 1.09

The extrusion rates in Examples F18, F21, and F24 were increased whilemaintaining the film gauge and blow-up ratio during the film blowingprocess as compared with the extrusion rate of ethylene polymers withoutbranched modifier. The maximum extrusion rate is determined to be theextrusion rate right before the film bubble becomes unstable and thenormal operation can no-longer be achieved. Likewise, the maximum linespeed is determined to be the line speed right before the film bubblebecomes unstable and the normal operation can no-longer be achieved. Themaximum line speed (%) is ratio of the maximum line speed of a blend tothe maximum line speed of the same ethylene polymer used in the blend.Significant improvements in haze were observed for the films withbranched modifier. The blown film processability, which is characterizedby the maximum line speed, is significantly improved. Meanwhile theprocessability for the blends with branched modifier is also superior tothe blend with 5% LD071.LR.

For reference purposes the following data is included.

TABLE 9 A: Selected Physical and Mechanical Properties of ZN-LLDPE^(#)and m-LLDPE films.* Comonomer MD 1% MD Type/ Secant Yield MD UltimateLoading MI Density Modulus Stress Properties Resin (mol %) (g/10 min)(g/cc) (MPa) (MPa) (%) (MPa) LL 1001^(#) C4/3.6 1.0 0.918 220 9.4 59057.0 LL 3001^(#) C6/3.6 1.0 0.917 200 9.0 500 58.0 Exact C6/>3.5 2.20.833 30 3.5 390 64.3 4056* Exact C6 > 3.5 2.2 0.889 56 5.4 400 84.84151* Exceed C6/3.5 1.0 0.912 131 7.4 500 72.6 1012* Exceed C6/1.5 1.00.918 183 9.2 540 74.5 1018* Exceed C6/<1.5 1.0 0.923 240 11.0 542.065.0 1023* B: Selected Physical and Mechanical Properties ofZN-LLDPE^(#) and m-LLDPE films.* MD Ultimate Elmendorf TearStrain/Stress MD TD TD/MD Dart Drop Resin Ratio (g/micron) (g/micron)Ratio (g/micron)* LL 1001^(#) 10.4 4.0 16.0 — 4.0 LL 3001^(#) 8.6 17.317.3 — 5.5 Exact 4056* 6.1 2.2 5.3 — 32.4 Exact 4151* 4.7 3.5 11.0 —37.0 Exceed 1012* 6.9 8.3 13.0 1.6 32.2 Exceed 1018* 7.2 11.0 18.1 1.622.4 Exceed 1023* 8.3 7.0 21.1 3.0 7.7 *Data in Tables 9A and 9B weretaken from ExxonMobil's technical data sheets.

Example 17

Unless otherwise indicated, all reactions in the following examples wereperformed using as-received starting materials without any purification.

Two branched polyethylene modifiers were made according to the proceduredescribed in Examples 5-13. The reaction conditions and characterizationdata are reported in Table 15.

TABLE 15 Modifier # 14 15 Polymerization temperature (° C.) 130 130Ethylene feed rate (SLPM) 8 8 1-hexene feed rate (g/min) 1.8 1.8 1,9decadiene feed rate (ml/min) 0.049 0.024 Catalyst Catalyst C Catalyst CIsohexane feed rate (g/min) 54 54 Polymer made (gram) 2378.1 377.4 Yield(gram/min) 9.51 9.435 Conversion (%) 87.7% 87.0% Catalyst efficiency (gpoly/g catalyst) 815,349 808,714 1-hexene content (wt %) 10.8 11.3 Tc (°C.) 90.5 85.9 Tm (° C.) 113.3 108.8 Heat of fusion (J/g) 123.0 128.7Mn_DRI (g/mol) 32,033 32,339 Mw_DRI (g/mol) 197,817 149,504 Mz_DRI(g/mol) 734,947 489,096 Mn_LS (g/mol) 80,867 45,787 Mw_LS (g/mol)397,764 215,440 Mz_LS (g/mol) 2,088,097 982,314 g′vis 0.5 0.64 I2(dg/min) <0.1 <0.1 I21 (dg/min) 0.04 0.43 Complex viscosity at 0.1rad/sec (Pa · s) 481000 316363 Complex viscosity at 100 rad/sec (Pa · s)2218 2310.3 Complex viscosity at 0.158 rad/sec (Pa · s) 325916 Complexviscosity at 1 rad/sec (Pa · s) 77136 Phase angle at complex modulus20.7 24 G* = 100,000 Pa (degrees)

The complex viscosity of the branched modifier polymer produced inModifier #14 and #15 was measured at a temperature of 190° C. over anangular frequency ranging from 0.01 to 398 rad/s. Significant shearthinning was observed. The ratio of the complex viscosity at a frequencyof 0.1 rad/s to the complex viscosity at a frequency of 100 rad/s was216.9 and 186.5 for materials produced in Modifier #14 and #15respectively.

The transient extensional viscosity of the modifier produced in Modifier#14 and #15 was measured at a temperature of 150° C. and a strain rateof 1 sec⁻¹.

Polyethylene Blends

The branched polyethylene modifiers and matrix polyethylene (Exceed™2018 PE, Enable™ 20-10 polyethylene, or POL-A) were compounded in a 1″Haake twin screw extruder with 0.05 wt % Irganox 1076™, 0.2 wt % Weston399™ and 0.08 wt % of FX592DA™. The Haake twin screw extruder was set at50 rpm and the melt temperature was targeted at 190° C.

Comparative blends with 5 wt % LDPE (ExxonMobil Chemical Company,Houston, Tex. LD071.LR™ PE, 0.924 g/cc, 0.70 dg/min, 190° C., 2.16 kg)and 0.05 wt % Irganox 1076™, 0.2 wt % Weston 399™ and 0.08 wt % ofFX592DA™ were also prepared under the conditions described above(referred to as Blends B, H, I, J, K and N), except that the extrudertemperatures were 190° C., 195° C., 190° C., and 185° C., respectively.The blend compositions and film properties are listed in Tables 10, 11,and 12.

TABLE 10 Blend Blend Blend Blend Blend A B C D E Exceed ™ LLDPE 1018 10095 95 95 90 LD071.LR (wt %) 0 5 Modifier 14 (wt %) 5 Modifier 15 (wt %)5 10 Draw Ratio 13.7 15.7 7.6 8.5 8.9 Melt strength (cN) 3.2 4.8 30.49.6 20.3 Complex viscosity at 1 6446 6676 7731 8076 8076 rad/s (Pa · s)Complex viscosity at 0.1 6839 rad/s (Pa · s) Complex viscosity at 68397497 6886 0.158 rad/s (Pa · s) Phase angle at complex 62 modulus G* =100,000 Pa (degrees) Strain Hardening Ratio 10.8

TABLE 11 Blend Blend Blend Blend Blend Blend F G H I J K POL-A 100 95 9590 80 70 LD071.LR 0 5 10 20 30 (wt %) Modifier 14 5 (wt %) Draw Ratio6.1 7.7 6.6 6.9 7.3 6.0 Melt strength 8.4 24.4 8.7 9.8 12.0 13.9 (cN)Complex 24870 25595 22557 viscosity at 1 rad/s (Pa · s) Complex 87088viscosity at 0.1 rad/s (Pa · s) Complex 67665 68592 60645 viscosity at0.158 rad/s (Pa · s) Phase angle 42 at complex modulus G* = 100,000 Pa(degrees) Strain 4.6 Hardening Ratio

TABLE 12 Blend L Blend M Blend N Enable 20-10 100 95 95 LD071.LR (wt %)0 5 Modifier 14 (wt %) 5 Draw Ratio 19.2 8.2 14.2 Melt strength (cN) 3.515 3.9 Complex viscosity at 1 7195 8660 7804 rad/s (Pa · s) Complexviscosity at 0.1 13511 rad/s (Pa · s) Complex viscosity at 12076 1597513484 0.158 rad/s (Pa · s) Phase angle at complex 50 modulus G* =100,000 Pa (degrees) Strain Hardening Ratio 3.3

All documents described herein are incorporated by reference herein forpurposes of all jurisdictions where such practice is allowed, includingany priority documents, related applications, and/or testing proceduresto the extent they are not inconsistent with this text, provided howeverthat any priority document not named in the initially filed applicationor filing documents is NOT incorporated by reference herein. As isapparent from the foregoing general description and the specificembodiments, while forms of the invention have been illustrated anddescribed, various modifications can be made without departing from thespirit and scope of the invention. Accordingly, it is not intended thatthe invention be limited thereby. Likewise, the term “comprising” isconsidered synonymous with the term “including” for purposes ofAustralian law. Likewise whenever a composition, an element or a groupof elements is preceded with the transitional phrase “comprising,” it isunderstood that we also contemplate the same composition or group ofelements with transitional phrases “consisting essentially of,”“consisting of,” “selected from the group of consisting of,” or “is”preceding the recitation of the composition, element, or elements andvice versa.

1.-9. (canceled)
 10. A blend comprising: 1) branched polyethylenemodifier comprising at least 50 mol % ethylene, one or more C₄ to C₄₀comonomers, and a polyene having at least two polymerizable bonds,wherein said branched polyethylene modifier has: a) a g′_(vis) of 0.70or less; b) an Mw of 100,000 g/mol or more; c) an Mw/Mn of 4.0 or more;d) a shear thinning ratio of 110 or more, e) a melt strength of 10 cN ormore; f) a complex viscosity at 0.1 rad/sec at 190° C. of at least130,000 Pa·s; and g) a phase angle of Z° or less where Z=138.3G*^((−0.142)), where G* is the complex modulus reported in Pascalsmeasured at 190° C. and the phase angle units are reported in degrees,wherein the G* is from 1,000 to 1,000,000 Pa; 2) polyethylene having adensity of 0.88 g/cc or more, a g′_(vis) of 0.97 or more.
 11. The blendof claim 10, wherein the complex viscosity at 0.1 rad/sec of thebranched polyethylene modifier is at least 320% greater than the complexviscosity at 0.1 rad/sec of the polyethylene prior to combination withthe branched polyethylene modifier.
 12. The blend of claim 10, whereinthe branched polyethylene modifier is present at 0.5 wt % to 10 wt %,based upon the weight of the blend.
 13. The blend of claim 10, whereinthe polyethylene comprises a copolymer of ethylene and one or more C₃ toC₂₀ alphaolefins and has an Mw of 20,000 to 1,000,000 g/mol.
 14. Theblend of claim 10, wherein the polyethylene has a density of 0.91 to0.96 g/cm³.
 15. (canceled)
 16. The blend of claim 10, wherein thebranched polyethylene modifier has a strain-hardening ratio of 1.5 orgreater.
 17. (canceled)
 18. The blend of claim 10, wherein where thepolyethylene has a g′_(vis) of 0.975 or more. 19.-22. (canceled)
 23. Afilm comprising the blend of claim
 10. 24. (canceled)
 25. The blend ofclaim 10, wherein the branched polyethylene modifier has an Mw of200,000 g/mol or more.
 26. The blend of claim 10, wherein the blend hasa melt strength at least 60% higher than the melt strength of thepolyethylene having a density of 0.88 g/cc or more and an Mw of 20,000g/mol or more used in the blend.
 27. The blend of claim 10, wherein theblend has a melt strength at least 100% higher than the melt strength ofthe polyethylene prior to combination with the branched polyethylenemodifier. 28.-30. (canceled)
 31. The blend of claim 10, wherein thecomposition of linear PE and branched modifier blend has a melt strengthratio of T or more, where T=1.6762[(η*_(blend) minus η*_(matrix))divided by (η*_(matrix))]−5, where η*_(blend) is the complex viscosityof the blend measured at 0.158 rad/sec and 190° C., and η*_(matrix) isthe complex viscosity of the linear polyethylene measured at 0.158rad/sec and 190° C.; and the ratio of melt strength to viscosity isdefined to be melt strength ratio is defined to be [(MS_(blend) minusMS_(matrix)) divided by (MS_(matrix))], where MS_(blend) is the meltstrength of the composition, MS_(matrix) is the melt strength of thelinear polyethylene. 32.-37. (canceled)
 38. The blend of claim 10,wherein the blend has a strain hardening ratio of at least 50% higherthan the strain hardening ratio of the polyethylene of step 2).
 39. Theblend of claim 10, wherein the polyene is selected from the groupconsisting of: 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene,1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene,1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene,tetrahydroindene, norbornadiene also known asbicyclo-(2.2.1)-hepta-2,5-diene, dicyclopentadiene,5-vinyl-2-norbornene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, and1,7-cyclododecadiene.
 40. The blend of claim 10, wherein thepolyethylene has an Mw of 20,000 g/mol or more, wherein the meltstrength ratio is Q or more, whereQ=0.0805[(η*_(modifier)−η*_(matrix))/(η*_(matrix))]+0.5, whereinη*_(modifier) is the complex viscosity of the modifier measured at 0.158rad/sec and 190° C., and η*_(matrix) is the complex viscosity of thepolyethylene measured at 0.158 rad/sec and 190° C.; and the meltstrength ratio is defined to be[(MS_(blend)−MS_(matrix))/(MS_(matrix))], where MS_(blend) is the meltstrength of the blend, MS_(matrix) is the melt strength of thepolyethylene.
 41. The blend of claim 10, wherein the branchedpolyethylene modifier has a complex viscosity ratio of Y or more, whereY=−0.27*(Log η*_(matrix))+1.4, and the complex viscosity ratio isdefined to be (Log η*_(modifier) minus Log η*_(matrix)) divided by (Logη*_(matrix)), wherein η*_(modifier) is the complex viscosity of themodifier measured at 0.1 rad/sec and 190° C., and η*_(matrix) is thecomplex viscosity of the polyethylene of step 2) below measured at 0.1rad/sec and 190° C.